Recording medium of stream data, and recording method and playback method of the same

ABSTRACT

Upon playback of stream data which is recorded while being appended with time stamp information in units of packets, time management is made using the time stamp information. A video playback time viewed from the user, which may be indicated by I-, B-, and P-picture display times, is different from the time of the time stamp information. For this reason, when time management for the stream data recorded on an information storage medium is made using only the time stamp information, display time control (video playback time control) for the user cannot be accurately done. In this invention, a time relationship table indicating the relationship between the time stamp information recorded in stream data at each I-picture start time position and display time information (PTS or field information) for the user is provided to a portion of management information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of Application No. PCT/JP00/00944, filed Feb. 18,2000.

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 11-039461, filed Feb. 18,1999, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an information storage medium whichrecords video data sent in, e.g., digital broadcast, or stream data sentwith a packet structure. Further, the present invention relates to adata structure of management information that pertains to stream datarecorded on the medium. Still further, the present invention relates toa recording method and playback method of the management information.

In recent years, TV broadcast has come into the era of digitalbroadcast. Accordingly, an apparatus for saving digital data of digitalTV broadcast as it is irrespective of their contents, i.e., a so-calledstreamer, has been demanded.

The current digital TV broadcast uses an MPEG transport stream. In thefuture, an MPEG transport stream will be used as a standard one in thefield of digital broadcast using moving picture.

In such digital broadcast, the contents (mainly, video information) tobe broadcasted are time-divided into groups of data each having apredetermined size (e.g., 188 bytes) called transport packets, andbroadcast data is sent in units of transport packets.

As a streamer for recording digital broadcast data, a home digital VCRsuch as D-VHS (digital VHS) or the like is currently commerciallyavailable. A streamer using D-VHS directly records a broadcastedbitstream on a tape. For this reason, a plurality of programs aremultiplexed and recorded on a video tape. upon playback, all data areoutput from the VCR to a set-top box (digital TV reception apparatus; tobe abbreviated as an STB hereinafter) either when they are played backfrom the beginning or the middle of the tape. In this STB, a desiredprogram is selected from the output data by user operation or the like.The selected program information is transferred from the STB to adigital TV receiver, and is played back (playback of video plus audio,etc.).

Since this D-VHS streamer uses a tape as a recording medium, it cannotattain quick random access, and it is difficult to quickly jump to adesired position of a required program so as to play it back.

As a promising candidate that can combat such shortcoming (difficulty ofrandom access) of the tape, a streamer that uses a large-size discmedium such as a DVD-RAM or the like has been proposed. In this case,management data must be inevitably recorded together with broadcast datain consideration of random access, special playback, and the like.

Note that a digital interface that complies with IEEE1394 or the likecan be used in data transfer between the STB as a digital TV receiverand the stream that uses large-capacity disc media such as a DVD-RAM andthe like, or between the streamer that uses large-capacity disc mediaand another streamer using a D-VHS or the like.

In this digital interface, video data/stream data are transferred inunits of transport packets received in digital broadcast.

For example, in a digital interface using IEEE1394, time stamp dataindicating the reception time is appended to each transport packet toguarantee real-time transfer of digital broadcast reception data, thustransferring the data.

Also, in order to guarantee real-time, seamless playback of the digitalbroadcast reception data recorded on an information storage medium suchas a DVD-RAM or the like, the time stamp data is simultaneously recordedtogether with each transport packet data.

In the aforementioned case, as stream data to be recorded on aninformation storage medium that uses large-capacity disc media such as aDVD-RAM and the like, each transport packet is recorded while beingappended with time stamp data. For this reason, time management is madeusing this time stamp data.

In digital TV, video data is broadcasted while its information iscompressed using a digital compression scheme called MPEG2. In MPEG2,P-picture information has only differential information from I-picture,and B-picture information has only differential information from I- andP-pictures. Therefore, B- or P-picture cannot be solely played back, andplayback from I-picture is required to playback these pictures.

Note that the video playback time viewed from the user, which isindicated by display times of I-, B-, and P-pictures, is different fromthe time stamp information. For this reason, when time management forstream data recorded on the information storage medium is made usingonly the time stamp data, control of the display time (video playbacktime) for the user cannot be accurately made.

The present invention has been made to solve the aforementioned problem,and has as its object to provide a data structure of managementinformation, and a recording method and playback method of the same,which make time management of stream data using time stamp data recordedin the stream data, and can make accurate time display control for theuser.

BRIEF SUMMARY OF THE INVENTION

In order to achieve the above object, according to the presentinvention, information (time relationship table; or playback time stamplist PTSL) that indicates the relationship between time stamp data(application time stamp ATS) recorded in stream data, and display timeinformation (PTS or field information) for the user is provided to aportion of management information (stream file information table SFIT).

On the other hand, the relationship among the display time information(PTS or field information) for the user, the start time position of eachI-picture (or access unit start map AUSM indicating stream object unitSOBU to which target access unit AU belongs), and time stamp data (ATS)can be indicated by the time relationship table (or PTSL).

An information medium according to the present invention has a data area(STREAM.VRO/SR_TRANS.SRO) where stream data (SOB or SOBU) can berecorded in a predetermined data recording unit (transportpacket/application packet), and a management area(STREAM.IFO/SR_MANGR.IFO) where management information (STRI) thatpertains to the stream data can be recorded. The management information(STRI) can record: first management information (ATS corresponding toI-picture transfer start time; or AUSM) used to access the stream data(access I-picture information or AU); and third management information(time relationship table; or PTSL) which is different from the firstmanagement information (AUSM), and indicates a relationship between thefirst management information and second management information (PTS; orcell start APAT=SC_S_APAT) used to access the stream data.

A recording method according to the present invention uses aninformation medium (201) which has a data area (STREAM.VRO) where streamdata (SOB or SOBU) can be recorded in a predetermined data recordingunit (packet), and a management area (STREAM.IFO) where managementinformation (STRI) that pertains to the stream data can be recorded. Themanagement information (STRI) can record: first management information(ATS corresponding to I-picture transfer start time; or AUSM) used toaccess the stream data (access I-picture information or AU); and thirdmanagement information (time relationship table; or PTSL) which isdifferent from the first management information (AUSM), and indicates arelationship between the first management information and secondmanagement information (PTS; or SC_S_APAT) used to access the streamdata (AU).

Upon recording on such information medium, the first managementinformation (ATS/AUSM) is extracted from stream data to be recorded(step S03); the second management information (PTS) is extracted fromthe stream data to be recorded (step S04); the stream data (packet data)is recorded on the information medium (201) (step S07); and the thirdmanagement information (time relationship table/PTSL) is recorded on themanagement area (STREAM.IFO/SR_MANGR.IFO) (step S11).

Alternatively, upon recording on such information medium, asynchronization process of a predetermined reference clock (SCR) isexecuted between a stream data supply device (STB unit) and a streamdata recording device (optical disc device or optical disc drive) (stepS54); the third management information (time relationship table; orPTSL) is corrected or modified on the basis of a result of thesynchronization process of the reference clock (SCR) (step S56); and thecorrected or modified third management information (time relationshiptable; or PTSL) is recorded in the management area(STREAM.IFO/SR_MANGR.IFO) on the information medium (201) (step S57).

A playback method according to the present invention uses an informationmedium (201) which has a data area (STREAM.VRO/SR_TRANS.SRO) wherestream data can be recorded in a second data unit (SOBU) including afirst data recording unit (application packet AP), and a management area(STREAM.IFO/SR_MANGR.IFO) where management information (STRI) thatpertains to the stream data can be recorded. The management information(STRI) can record: first management information (ATS corresponding toI-picture transfer start time; or AUSM) used to access the stream data(access I-picture information or AU); and third management information(time relationship table; or PTSL) which is different from the firstmanagement information (AUSM), and indicates a relationship between thefirst management information and second management information (PTS; orSC_S_APAT) used to access the stream data (AU).

Upon playing back the stream data from such information medium (201),when the stream data has a plurality of continuous second data units(for example, SOBU#1 and SOBU#2), a position difference (PTS offset orAP which is not played back in FIG. 29( g)) from a neighboring boundaryposition of the plurality of continuous second data units (SOBU#1 andSOBU#2) to a position (SC_S_APAT) of the first data recording unit (AP)indicated by the second management information (PTS; or SC_S_APAT) ischecked (step S24); read of the stream data recorded on the informationmedium (201) starts from the neighboring boundary position (step S30)but read data until the position (SC_S_APAT) of the first data recordingunit (AP) indicated by the position difference are discarded or ignored(step S31); and playback (display of playback information) of the streamdata recorded on the information medium (201) starts from the position(SC_S_APAT) of the first data recording unit (AP) indicated by theposition difference (step S32).

Alternatively, upon playback from such information medium, a startaddress of the second data unit (SOBU) including the first managementinformation (ATS corresponding to I-picture transfer start time; orAUSM) is checked (step S45); playback information other than an accessposition (access position of I-picture information or AU) of the streamdata indicated as the first management information (AUSM) is discardedor ignored using the checked start address of the second data unit (stepS47); and only playback information at the access position (I-pictureinformation; or AU) of the stream data is sequentially played back ordisplayed (step S49).

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a view for explaining the data structure of stream dataaccording to an embodiment of the present invention;

FIG. 2 is a view for explaining the directory structure of data filesaccording to an embodiment of the present invention;

FIG. 3 is a view for explaining the recorded data structure (especially,the structure of management information) on an information medium(recordable/reproducible DVD disc) according to an embodiment of thepresent invention;

FIG. 4 is a view for explaining the relationship among stream objects(SOB), cells, program chains (PGC), and the like in the presentinvention;

FIG. 5 is a view for explaining the contents of a stream block size,stream block time difference, and the like in time map information;

FIG. 6 is a view for explaining the cell range designation method in anoriginal cell and user-defined cell;

FIG. 7 is a view for explaining the recorded data structure (especially,the structure of playback end position information/resume information,VMGI management information/recording time information, and the like) onan information medium (recordable/reproducible DVD disc) according toanother embodiment of the present invention;

FIG. 8 is a view for explaining the internal structure of a PES headershown in FIG. 1 and the like;

FIG. 9 is a view for explaining the internal structure of a stream blockheader shown in FIG. 1;

FIG. 10 is a view for explaining the internal structure of a sector dataheader shown in FIG. 1;

FIG. 11 is a view for explaining another example of time map informationin an embodiment of the present invention;

FIG. 12 is a view for explaining an example of the internal structure (astream pack containing application packets and a stream pack containingstuffing packets) of a sector that forms a stream block (SOBU);

FIG. 13 is a view for explaining the internal data structure ofmanagement information (STREAM.IFO or SR_MANGR.IFO in FIG. 2) of thestreamer;

FIG. 14 is a view for explaining the internal data structure of PGCinformation (ORG_PGCI/UD_PGCIT in FIG. 3 or PGCI#i in FIG. 13);

FIG. 15 is a view for explaining the internal data structure of a streamfile information table (SFIT);

FIG. 16 is a view exemplifying the correspondence between an access unitstart map (AUSM) and stream object unit (SOBU);

FIG. 17 is a view exemplifying the correspondence between an access unitstart map (AUSM) and access unit end map (AUEM), and stream object unit(SOBU);

FIG. 18 is a view for explaining the relationship between cellsdesignated by an original or user-defined PGC and SOBUs corresponding tothese cells via time map information;

FIG. 19 is a block diagram for explaining the arrangement of a streamdata recording/playback apparatus (optical disc device/streamer, STBunit) according to an embodiment of the present invention;

FIG. 20 is a view for explaining a time relationship table indicatingthe relationship between the display time and data transfer time in anembodiment of the present invention;

FIG. 21 is a view for explaining the relationship between the displaytime and data transfer time in an embodiment of the present invention;

FIG. 22 is a view for explaining the relationship between the videoinformation compression method in MPEG and transport packets, and therelationship between transport packets in MPEG and application packetsin the streamer;

FIG. 23 is a view for explaining the correspondence among the digitalbroadcast contents, the video data transfer format in IEEE1394, andstream packs in the streamer;

FIG. 24 is a flow chart for explaining the recording sequence of streamdata according to an embodiment of the present invention;

FIG. 25 is a flow chart for explaining the recording sequence ofencrypted stream data according to an embodiment of the presentinvention;

FIG. 26 is a flow chart for explaining the playback sequence of streamdata according to an embodiment of the present invention;

FIG. 27 is a flow chart for explaining the special playback sequence ofstream data according to an embodiment of the present invention;

FIG. 28 is a view for explaining a time relationship table indicatingthe relationship between the display time and data transfer time inanother embodiment of the present invention; and

FIG. 29 is a view for explaining the way packets (AP) in stream data(SOBU) are played back in an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A stream data storage medium according to an embodiment of the presentinvention, the data structure of management data that pertains to streamdata recorded on the medium, a recording method and playback method ofthe management information, and so on will be described hereinafter withreference to the accompanying drawings.

FIG. 1 is a view for explaining the data structure of stream dataaccording to an embodiment of the present invention. The data structureof stream data recorded on an information storage medium will bedescribed using FIG. 1.

Stream data (STREAM.VRO) 106 (FIG. 1( a)) recorded on an informationstorage medium (201 in FIG. 3 and the like) such as a DVD-RAM disc orthe like are combined as stream objects (to be abbreviated as SOBshereinafter as needed) in units of contents of video information instream data. Each SOB is formed of stream data obtained by singlereal-time, continuous recording.

As shown in FIG. 1( b), stream data recorded on the information storagemedium are recorded together as stream objects (SOB) #A•298 and #B•299in units of contents of video information in the stream data.

FIGS. 1( b) to (k) show details of contents of one SOB#A•298 of aplurality of stream objects (SOB#A, #B, . . . ).

Upon recording stream data (STREAM.VRO) 106 on a DVD-RAM disc, each datais recorded using 2,048-byte sectors as minimum units. Furthermore, 16sectors form one ECC block, and in one ECC block, data are interleaved(the order of data is re-arranged) and a correction code for errorcorrection is appended.

In this embodiment, a stream block (or stream object unit SOBU) isformed by one or more (typically, 2) of ECC blocks as a unit, and streaminformation undergoes recording, partial erase, edit, and the like inunits of stream blocks (or SOBUs).

In this embodiment, the number of ECC blocks that form a stream blockcan be determined in accordance with the transfer rate of stream data(STREAM.VRO) 106 to be transferred.

For example, in an example shown in FIGS. 1( c) and (d), stream block #1is formed by two ECC blocks #α and #β, and stream block #2 is formed bythree ECC blocks #γ, #δ, and #ε. A DVD streamer forms one stream block(or SOBU) using two ECC blocks (32 sectors).

Each ECC block is made up of 16 sectors, as shown in FIG. 1( e).Therefore, as can be seen from FIGS. 1( c) to (e), stream block (orSOBU) #1 made up of two ECC blocks corresponds to 32 sectors (sectorsNo. 0 to No. 31).

More specifically, if one sector=2 k bytes, a stream block (SOBU) has afixed size of 64 k bytes (32 sectors) upon practicing the presentinvention.

Stream data (STREAM.VRO) 106 is recorded on the information storagemedium as pairs of time stamps and transport time packets, as shown inFIG. 1( g).

In such case, pack headers 11 and 12 that record system clockinformation (system clock reference SCR) and the like and PES headers 13and 14 are allocated at the head positions of the respective sectors, asshown in FIG. 1( f). Sector data header 17 is recorded immediately afterPES header 14, but stream block header 16 is recorded in only the firstsector of each stream block (or SOBU) in place of the sector dataheader.

Note that stream block header 16 or sector data header 17 can havecontents corresponding to an application header (to be described later)(see FIG. 9 or FIG. 10).

Sector data header 17 in FIG. 1( f) indicates data layout information indata areas 22 and 23.

Data areas 21 and 22 (or 23) in FIG. 1( f) are stuffed in turn with timestamps (corresponding to ATS shown in FIG. 20, FIG. 29, etc.) andtransport packets (corresponding to packets shown in FIG. 22 or FIG. 23or application packets AP in FIG. 29), as shown in FIG. 1( g).

In the example shown in FIG. 1( g), single transport packet d isrecorded across a plurality of sectors (No. 0 and No. 1). Such transportpacket d corresponds to a partial packet in FIG. 22 or FIG. 23.

Digital broadcast adopts a multi-program compatiblemultiplexing/demultiplexing scheme called a transport stream, and onetransport packet often normally has a size of 188 bytes (or 183 bytes).

On the other hand, one sector size is 2,048 bytes, as described above,and each of data areas 21, 22, and 23 (FIG. 1( f)) can recordapproximately 10 transport packets for digital broadcast even aftervarious header sizes are subtracted.

Each transport packet is made up of a corresponding one of transportpacket headers 61 to 64 (corresponding to 511 in FIG. 23( b) to bedescribed later), and a corresponding one of payloads 71 to 75(corresponding to 512 in FIG. 23( b) to be described later) that recorddata, as shown in FIG. 1( h).

Each of payloads 71 to 75 records MPEG-encoded I-picture information 31,B-picture information 33, B-picture information 34, and P-pictureinformation 32, as shown in FIG. 1( i).

In the first transport packet that records I-picture information 31,random access indicator 503 (see FIG. 23( a)) is set with flag=“1”. Onthe other hand, in the first transport packets of B-picture informationand P-picture information (32 to 34), payload unit start indicator 501(see FIG. 23( a)) is set with flag=“1”.

In each picture information (31 to 34) divisionally recorded in payloads71 to 75, picture header information 41, picture compressed information42 (I-picture compressed information 42 for I-picture information 31) asactual picture information are recorded, as shown in FIG. 1( j).

Each picture header information 41 records header identificationinformation 51, picture identification information 52 that can identifyI-, B-, or P-picture, PTS (presentation time stamp) information 53indicating the display timing of a decoder output, and DTS (decode timestamp) information 54 indicating the timing at which a decoder begins todecode, as shown in FIG. 1( k). Such picture header information 41 isincluded in advance in broadcast reception information.

In stream data recorded on the information storage medium, a specificpicture position can be identified using picture identificationinformation 52 shown in FIG. 1( k).

Alternatively, since PTS information 53 is recorded in picture headerinformation 41, as shown in FIGS. 1( j) and (k), the decoder can startdisplay using this value.

FIG. 2 is a view for explaining the directory structure of data filesaccording to an embodiment of the present invention. The contents (filestructure) of information recorded on the information storage mediumaccording to an embodiment of the present invention will be explainedbelow.

Each information recorded on an information storage medium such as aDVD-RAM disc or the like has a hierarchical file structure. Videoinformation and stream data information to be explained in thisembodiment are stored in subdirectory 101 named DVD_RTR directory (orDVD_RTAV) 102.

DVD_RTR (DVD_RTAV) directory 102 stores data file 103 having thefollowing contents.

More specifically, as a group of management information (navigationdata), RTR.IFO (VR_MANGR.IFO) 104, STREAM.IFO(SR_MANGR.IFO/SR_MANGR.BUP) 105, and SR_PRIVT.DAT/SR_PRIVT.BUP 105 a arestored.

As a data main body (contents information), STREAM.VRO (SR_TRANS.SRO)106, RTR_MOV.VRO (VR_MOVIE.VRO) 107, RTR_STO.VRO (or VR_STILL.VRO) 108,and RTR_STA.VRO (or VR_AUDIO.VRO) 109 are stored.

Root directory 100 as an upper layer of subdirectory 101 including datafile 103 can be provided with subdirectory 110 for storing other kindsof information.

This subdirectory includes, as its contents, video title set VIDEO_TS111 that stores video programs, audio title set AUDIO_TS 112 that storesaudio programs, subdirectory 113 for saving computer data, etc.

Data which is transmitted on a wired or wireless data communication pathin the form of a packet structure and is recorded on an informationstorage medium while holding the packet structure is called “streamdata”.

The stream data themselves are recorded together with file nameSTREAM.VRO (or SR_TRANS.SRO) 106. A file that records managementinformation of the stream data is STREAM.IFO (or SR_MANGR.IFO and itsbackup file SR_MANGR.BUP) 105.

A file that records analog video information which is used in a VCR(VTR) or conventional TV and is digitally compressed based on MPEG2 isRTR MOV.VRO (or VR_MOVIE.VRO) 107, a file that collects still pictureinformation including postrecorded audio, background audio, or the likeis RTR_STO.VRO (or VR_STILL.VRO) 108, and its postrecorded audioinformation file is RTR STA.VRO (or VR AUDIO.VRO) 109.

FIG. 3 is a view for explaining the recorded data structure (especially,the structure of management information) on an information medium(recordable/reproducible DVD disc) according to an embodiment of thepresent invention.

In an area sandwiched between the ends of inner circumferentialdirection 202 and outer circumferential direction 203 of informationstorage medium 201 shown in FIG. 3( a), lead-in area 204, volume & filestructure information 206 that records file system information, dataarea 207, and lead-out area 205 are present, as shown in FIG. 3( b).Lead-in area 204 is made up of an emboss zone and rewritable data zone,and lead-out area 205 is made up of a rewritable data zone. Data area207 is also made up of a rewritable data zone.

Data area 207 can record computer data and audio & video data together,as shown in FIG. 3( c). In this example, audio & video data area 210 issandwiched between computer data areas 208 and 209.

Audio & video data area 210 can record real-time video recording area221 and stream recording area 222 together, as shown in FIG. 3( d).(Either of real-time video recording area 221 or stream recording area222 can be used.)

As shown in FIG. 3( e), real-time video recording area 221 records RTRnavigation data RTR.IFO (VR_MANGR.IFO) 104, movie real-time video objectRTR_MOV.VRO (VR_MOVIE.VRO) 107, still picture real-time video objectRTR_STO.VRO (VR_STILL.VRO) 108, and audio object RTR_STA.VRO(VR_AUDIO.VRO) 109 such as postrecorded audio or the like, which areshown in FIG. 2.

Also, as shown in FIG. 3( e), stream recording area 222 records streamernavigation data STREAM.IFO (SR_MANGR.IFO/SR_MANGR.BUP) 105 and transportbitstream data STREAM.VRO (SR_TRANS.SRO) 106, which are shown in FIG. 2.

Note that stream recording area 222 can also record navigation dataSR_PRIVT.DAT/SR_PRIVT.BUP 105 a unique to an application shown in FIG.2, although not shown in FIGS. 3( d) and (e).

This SR_PRIVT.DAT 105 a is navigation data unique to an individualapplication connected (supplied) to the streamer, and need not berecognized by the streamer.

STREAM.IFO (or SR_MANGR.IFO) 105 as management information that pertainsto stream data has a data structure shown in FIG. 3( f) to (i).

More specifically, as shown in FIG. 3( f), STREAM.IFO (or SR_MANGR.IFO)105 is comprised of video manager (VMGI or STR_VMGI) 231, stream fileinformation table (SFIT) 232, original PGC information (ORG_PGCI) 233,user-defined PGC information table (UD_PGCIT) 234, text data manager(TXTDT_MG) 235, and manufacturer information table (MNFIT) orapplication private data manager (APDT_MG) 236 that manages navigationdata SR_PRIVT.DAT 105 a unique to an application.

Stream file information table (SFIT) 232 shown in FIG. 3( f) can containstream file information table information (SFITI) 241, one or morepieces of stream object information (SOBI) #A•242, #B•243, . . . ,original PGC information general information 271, and one or more piecesof original cell information #1•272, #2•273, . . . as shown in FIG. 3(g).

Each stream object information (e.g., SOBI#A•242) shown in FIG. 3( g)can contain stream object general information (SOBI_GI) 251, time mapinformation 252, and the like, as shown in FIG. 3( h).

Each original cell information (e.g., #1272; corresponding to SCI shownin FIG. 14 to be described later) shown in FIG. 3( g) can contain celltype 281 (corresponding to C_TY shown in FIG. 14 to be described later),cell ID 282, corresponding cell start time (corresponding to SC_S_APATshown in FIG. 6( b), FIG. 14, etc. to be described later) 283,corresponding cell end time (corresponding to SC_E_APAT shown in FIG. 6(b), FIG. 14, etc. to be described later) 284, PTS offset 9, and timerelationship table 2, as shown in FIG. 3( h).

Note that PTS offset 9 indicates the difference between the PTS(presentation time stamp value) of a display start picture of anoriginal cell (details of the original cell will be explained later) andthat of I-picture located immediately before the display start picture(details will be explained later with reference to FIG. 20).

Time map information 252 in FIG. 3( h), which is contained in SOBI#A inFIG. 3( g) can include stream block number 261, first stream block size262, first stream block time difference 263, second stream block size264, second stream block time difference 265, . . . , as shown in FIG.3( i). The contents of each stream block time difference that forms timemap information 252 will be explained later with reference to FIG. 5.

FIG. 4 is a view for explaining the relationship among stream objects(SOB), cells, program chains (PGC), and the like in an embodiment of thepresent invention. The relationship between SOB and PGC in the presentinvention will be explained below using an example shown in FIG. 4.

Stream data recorded in stream data (STREAM.VRO or SR_TRANS.SRO) 106form stream blocks as sets of one or more ECC blocks, and recording, apartial erase process, and the like are done in units of stream blocks.The stream data form groups called stream objects in units of contentsof information to be recorded (e.g., in units of programs in digitalbroadcast).

Management information (original PGC information 233, user-defined PGCinformation table 234, or the like) for each stream object (SOB#A,SOB#B) recorded in STREAM.VRO (SR_TRANS.SRO) 106 is recorded innavigation data STREAM.IFO (SR_MANGR.IFO) 105 (see lowermost portion inFIG. 4 and FIGS. 3( e) and (f)).

Two pieces of management information (STREAM.IFO 105) for stream objects#A•298 and #B•299 in FIG. 4 are recorded as two pieces of stream objectinformation (SOBI) #A•242 and #B•243 in stream file information table(SFIT) 232, as shown in FIGS. 3( f) and (g).

Each of stream object information (SOBI) #A•242 and #B•243 contains timemap information 252 that mainly describes the data size, timeinformation, and the like in units of stream blocks.

Upon playing back stream data, information (corresponding to PGCI#i inFIG. 14 to be described later) of a program chain (PGC) made up of oneor more successive cells is used. Stream data can be played back inaccordance with the order in which the cells that form this PGC are set.

There are two types of PGCs, i.e., original PGC 290 (ORG_PGCI•233 inFIG. 3( f)) which can continuously play back all stream data recorded inSTREAM.VRO (SR_TRANS.SRO) 106, and user-defined PGCs #a•293 and #b•296(corresponding to the contents of UD_PGCIT•234 in FIG. 3( f)) that canset arbitrary locations and order of user choice.

Original cells #1•291 and #2•292 that form original PGC 290 basicallyhave one-to-one correspondence with stream objects #A•298 and #B•299.

By contrast, user-defined cells #11•294, #12•295, and #31•297 that formthe user-defined PGC can set arbitrary locations within the range of onestream object #A•298 or #B•299.

Note that the sector size of each stream block can be variously set. Asa preferred embodiment, a stream object unit (SOBU) made up of two ECCblocks (32 sectors) and having a constant size (64 k bytes) can be usedas a stream block like stream block #1 in FIG. 4.

When the stream block is fixed to be an SOBU having a constant size(e.g., 2 ECC blocks=32 sectors=64 k bytes), the following merits areobtained.

(01) Even when stream data is erased or rewritten in units of SOBUs, anECC block of that SOBU does not influence ECC blocks of SOBUs other thanthe SOBU to be erased or rewritten. For this reason, ECCdeinterleave/interleave upon erase or rewrite (for SOBUs other than theSOBU to be erased or rewritten) need not be done; and

(02) An access position to recorded information in an arbitrary SOBU canbe specified by the number of sectors (or a parameter corresponding tothe number of sectors; e.g., information of stream packs or applicationpackets therein shown in FIG. 10 to be described later). For example,when the middle position of given SOBU#k is to be accessed, the 16thsector position (or application packet position corresponding to the16th sector position) from the boundary between SOBU#k−1 and SOBU#k canbe designated.

FIG. 5 is a view for explaining the contents of the stream block sizeand stream block time difference in the time map information. Thecontents of individual data in time map information 252 will beexplained below using FIG. 5.

As exemplified in FIG. 5( f), FIG. 5( g), and FIG. 5( h), stream object(SOB) #A•298 is made up of stream blocks #1 and #2.

In the example shown in FIGS. 5( f) and (h), the data size of streamblock #1 that forms SOB#A•298 is defined by two ECC blocks (#α and #β),i.e., 32 sectors (FIGS. 5( e) and (i)). That is, first stream block size262 (FIG. 5( j)) in time map information 252 (FIG. 5( a) and FIG. 5( k))is 32 sectors (64 k bytes).

Stream block #1 (FIG. 5( f)) located at the head position of SOB#A•298(FIG. 5( g)) has sector No. 0 (FIG. 5( e)) at its head position, andtime stamp a is recorded at the head position of data area 21 (FIG. 5(d)) included in sector No. 0.

Subsequent stream block #2 (FIG. 5( f)) of SOB#A•298 (FIG. 5( g)) hassector No. 32 (FIG. 5( e)), and time stamp p (FIG. 5( c)) is recorded atthe head position of data area 311 (FIG. 5( d)) included in sector No.32.

As shown in FIG. 5( c), the time stamp value of the first stream data instream block #1 is time stamp a, and that of the first stream data ofnext stream block #2 is time stamp p.

The value of first stream block time difference 263 in FIG. 5( b)(corresponding to stream block time difference 263 in FIG. 3( i)) isgiven by the difference ([time stamp p]−[time stamp a]) between timestamps a and p.

Note that time map information 252 in FIG. 5( a) can be handled asinformation including access data unit AUD in stream object informationSOBI to be described later with reference to FIG. 15. Information(access unit start map AUSM and the like) included in this AUD canspecify an SOBU that includes information to be accessed.

FIG. 6 is a view for explaining the cell range designation method in anoriginal cell and user-defined cell. The cell range can be designated bydesignating the start and end times.

More specifically, the values of first time stamp a and last time stampz (FIG. 6( c)) in corresponding stream object #A•298 (FIG. 6( f)) areused as the values of corresponding cell start and end times 283 and 284(FIG. 6( b)) in an original immediately after recording of stream data.

By contrast, the time range in user-defined cell #12•295 (FIG. 6( k))can designate arbitrary times. For example, as shown in FIGS. 6( i) and(j), the values of time stamps d and n corresponding to designatedtransport packets d and n can be set as the values of corresponding cellstart and end times 331 and 332.

FIG. 6( f) exemplifies a case wherein stream object (SOB) #A•298 is madeup of two stream blocks #1 and #2.

In the example shown in FIGS. 6( e) and (g), stream block #1 consists of32 sectors (sectors No. 0 to No. 31), and stream block #2 consists of 48sectors (sectors No. 32 to No. 79).

First sector No. 0 in stream block #1 is comprised of pack header 1, PESheader 6, stream block header 11, data area 21, and the like, as shownin FIGS. 6( e) and (d).

On the other hand, trailing-side sector No. 78 in stream block #2 iscomprised of pack header 3, PES header 8, sector data header 13, dataarea 24, and the like, as shown in FIGS. 6( e) and (d).

Furthermore, sector No. 1 in FIG. 6( g) records pack header 2, sectordata header 12, data area 22, and the like, as shown in FIG. 6( h), andsector No. 33 in FIG. 6( g) records sector data header 321, data area312, and the like, as shown in FIG. 6( h).

Data area 21 shown in FIGS. 6( d) and (h) records pairs of time stamps ato d and transport packets a to d, as shown in FIGS. 6( c) and (i).

Also, data area 24 in FIG. 6( d) records a plurality of pairs of timestamps and transport packets, end code 32 that follows the last pair oftime stamp z+transport packet z, and padding area 37.

Data area 22 shown in FIG. 6( h) includes transport packet d thatincludes the remaining contents of transport packet d in data area 21,as shown in FIG. 6( i). That is, in this example, the contents oftransport packet d are divisionally recorded in data areas 21 and 22.

The former half (on the data area 21 side) of transport packet d in FIG.6( i) corresponds to a tail-side partial packet in FIG. 23( f) to bedescribed later, and the latter half (on the data area 22 side) oftransport packet d in FIG. 6( i) corresponds to a head-side partialpacket in FIG. 23 (g) to be described later.

Furthermore, data area 312 in FIG. 6( h) records a pair of time stamp nand transport packet n, and other similar pairs, as shown in FIG. 6( i).

Note that start time 331 (FIG. 6( j)) of a cell corresponding to aposition where the user or the like designates the playback start timeis designated by time stamp d (FIG. 6( i)) for the total of twotransport packets d divisionally recorded in data areas 21 and 22.

When a transport packet is changed to read an application packet (AP)and APAT represents the application packet arrival time, cell start time331 can be expressed by cell start APAT.

On the other hand, end time 332 (FIG. 6( j)) of a cell corresponding toa position where the user or the like designates the playback end timeis designated by time stamp n (FIG. 6( i)) for transport packet n indata area 312. This cell end time 332 can be expressed as cell end APAT.

The aforementioned cell start time (cell start APAT) 331 and cell endtime (cell end APAT) 332 are recorded in user-defined cell information#12•295, as shown in FIG. 6( k).

This user-defined cell information #12•295 can be recorded inuser-defined PGC information table 234 shown in FIG. 3( f) or the lowerportion in FIG. 4.

The cell start start/end time information that pertains to theuser-defined cell information (information of a user-defined PGC) hasbeen explained. On the other hand, cell start/end time information thatpertains to original cell information (information of an original cell)can be exemplified as follows.

More specifically, head-side time stamp a in FIG. 6( c) can indicatecorresponding cell start time 293 in FIG. 6( b), and tail-side timestamp z can indicate corresponding cell end time 284.

Corresponding cell start time 283 in FIG. 6( b) can correspond to cellstart APAT (including stream cell start APAT (SC_S_APAT) or erase startAPAT (ERA_S_APAT) to be described later).

Corresponding cell end time 284 in FIG. 6( b) can correspond to cell endAPAT (including stream cell end APAT (SC_E_APAT) or erase end APAT(ERA_E_APAT) to be described later).

The aforementioned cell start time (cell start APAT) 283 and cell endtime (cell end APAT) 284 are recorded in original cell information#1•272, as shown in FIG. 6( a).

This original cell information #1•272 can be recorded in original cellPGC information 233 shown in FIG. 3( f) or the lower portion in FIG. 4.

FIG. 7 is a view for explaining the recorded data structure (especially,the structure of playback end position information/resume information,VMGI management information/recording time information, and the like) onan information medium (recordable/reproducible DVD disc) according toanother embodiment of the present invention.

Since the data format shown in FIG. 7( a) to (f) is the same as thatshown in FIG. 3( a) to (f), a description thereof will be omitted.

Video manager (STR_VMGI) 231 in FIG. 7( f) contains playback endposition information (resume information) 6110, video manager managementinformation (VMGI_MAT) 6111, and the like, as shown in FIG. 7( g).

Playback end position information (resume information) 6110 includesoriginal PGC number 6210, original cell number 6220, playback endposition time (resume time) information 6230, and the like, as shown inFIG. 7( h).

Video manager management information (VMGI_MAT) 6111 includes time zone(TM_ZONE) 6240.

Upon completion of playback of the recorded stream block (or originalcell), playback end position information 6110 can be recorded in videomanager information 231 in a management information recording area(STREAM.IFO) in FIG. 7( e) as resume information.

Note that time information 6230 included in playback end positioninformation 6110 is recorded using a time stamp (ATS) value. However,the present invention is not limited to such specific value, and a PTSvalue (or a total number of fields from the cell playback startposition) may be recorded as time information 6230.

Time zone (TM ZONE) 6240 includes information of a recording time(REC_TM), as shown in FIG. 7( i).

The information of the recording time (REC_TM) includes a time zone type(TZ_TY) used to identify if REC_TM is based on universal time coordinate(UTC) or specific local time, and a time zone offset (TZ_OFFSET) thatdescribes the time offset of REC_TM from UTC in units of minutes.

The recording time (REC_TM) may be described in the form of a cell starttime (SC_S_APAT) shown in FIG. 6( b) and the like or in the form ofplayback time (presentation time PTM) of that cell.

There are two types of recording time (REC_TM). The first one is astream object recording time (SOB_REC_TM), and the second one is a playlist creation time (PL_CREATE_TM).

Note that the time at which a stream object (SOB) corresponding to anoriginal cell was recorded is indicated by SOB_REC_TM.

Note that the play list is a list of a portion of a program. With thisplay list, the user can define an arbitrary playback sequence (for thecontents of a program). The time at which such play list was created isindicated by PL_CREATE_TM.

FIG. 8 is a view for explaining the internal structure of a PES headershown in FIG. 1 and the like.

PES header 601 in FIG. 8( a) includes packet start code prefix 602,stream ID 603, playback time stamp 604, and the like, as shown in FIG.8( b). This PES header 601 corresponds to the PES header shown in FIG.1( f), FIG. 5( d), FIG. 6( d), etc.

A stream PES header in FIG. 8( d) includes a packet start code prefix,stream ID (private stream 2), PES packet length, substream ID, and thelike, as shown in FIG. 8( c). This stream PES header is the same as thatshown in FIG. 22 to be described later, and has contents correspondingto PES header 601 in FIG. 8( a).

When the PES header in FIG. 1( f) has the internal structure of PESheader 601 shown in FIG. 8( a), if stream ID 603 (FIG. 8( b)) of thisPES header is “10111110”, a packet having this PES header is defined tobe a padding packet (see FIG. 12( g) to be described later) in MPEG.

On the other hand, if substream ID 603 (substream ID in FIG. 8( c)) is“00000010”, a packet with that PES header includes stream recordingdata.

In stream block #1 in FIG. 1( c), last transport packet g (FIG. 1( g))is present within sectors No. 0 to No. 31 (FIG. 1( e)). However, instream block #2 (FIGS. 1( e) and (g)), since the user or the like endsvideo recording halfway through, the last transport packet (not shown)is allocated in a sector before the last one, and the last sector (notshown) is often a free area where no stream data is recorded. In thiscase, the padding packet (padding packet 40 in FIG. 12( g) to bedescribed later) is recorded in the last sector.

FIG. 9 is a view for explaining the internal structure of the streamblock header shown in FIG. 1.

As shown in FIG. 9( a), stream block header 11 has contentscorresponding to a substream ID, application header, application headerextension, stuffing byte, and the like.

The 1-byte application header extension (option) describes 1-bitAU_START, 1-bit AU_END, and 2-bit COPYRIGHT.

When AU_START is set at “1”, it indicates that a related applicationpacket (e.g., AP in FIG. 29) includes a random access entry point (startof a random access unit) within the stream.

When AU_END is set at “1”, it indicates that a related applicationpacket is the last packet of the random access unit.

COPYRIGHT describes the state of the copyright of a related applicationpacket.

Stream block header 11 includes transport packet information 611, streamblock information 612, sector data header information 613, and the like,as shown in FIG. 9( b).

Transport packet information 611 in FIG. 9( b) is the same as transportpacket information 611 in FIG. 9( c).

Stream block information 612 in FIG. 9( b) which records informationthat pertains to the entire stream block corresponds to recording time622 (information of year, month, day, and time recorded on informationstorage medium 201), transport packet attribute 623 (attributeinformation that pertains to a transport packet), stream block size 624(the data size of the corresponding stream block (e.g., the data sizecan be expressed by the number of ECC blocks)), stream block timedifference 625, and the like in FIG. 9( c).

Taking FIG. 5( b) as an example, time range information in thecorresponding stream block is computed by [stream block timedifference]=[first time stamp value in stream block #2]−[value of timestamp a]. This [stream block time difference] corresponds to streamblock time difference 625.

Sector data header information 613 in FIG. 9( b) corresponds to firstaccess point 626 and transport packet connection flag 627 in FIG. 9( c).This sector data header information 613 includes information similar tosector data 12 shown in FIG. 10 to be described later.

Transport packet information 611 in FIG. 9( c) includes the number 631of transport packets (the number of application packets), transportpacket mapping table 632, and the like, as shown in FIG. 9( d).

Note that the number of application packets in FIG. 9( d) corresponds toAP_Ns in FIG. 10( c) or FIG. 11 to be described later.

The number 631 of transport packets (application packets) in FIG. 9( d)can include I-picture mapping table 641, B/P-picture mapping table 642,and the like, as shown in FIG. 9( e).

Transport packet mapping table 632 in FIG. 9( d) can include videopacket mapping table 643, audio packet mapping table 644, program uniqueinformation mapping table 645, and the like.

Each mapping table (FIG. 9( e)) in transport packet mapping table 632has a bitmap format.

For example, when n transport packets (application packets) are recordedin one stream block, the number 631 of transport packets (the number ofapplication packets) in FIG. 9( d) assumes a value “n”.

Furthermore, each of mapping tables 643 to 645 consists of “n-bit data”,and one bit is assigned to each of transport packets (applicationpackets) which line up in the stream block from the head side.

FIG. 10 is a view for explaining the internal structure of the sectordata header shown in FIG. 1.

For example, sector data header 17 in FIG. 1( f) indicates data layoutinformation in data areas 22 and 23, and corresponds to sector dataheader 12 (corresponding to an application header in FIG. 10( d)) inFIG. 10( a).

Sector data header 12 has an internal structure including first accesspoint 651 and transport packet connection flag 652, as shown in FIG. 10(b).

As shown in FIG. 10( d), one stream pack having a size of 2,048 bytes,which is the same as the sector size, consists of a pack header andstream PES header. The stream PES header contains an application packetheader corresponding to a portion of sector data header 12 in FIG. 10(a) or stream block header 11 in FIG. 9( a).

As shown in FIG. 10( c), this application packet header includes:

-   -   the version of the application packet header format;    -   the number AP_Ns of application packets (transport packets)        which start within the stream pack of interest;    -   first application packet time stamp position FIRST_AP_OFFSET        which describes the position of a time stamp of the first        application packet which starts within the stream pack of        interest by a relative value from the first byte of that stream        pack;    -   extension header information EXTENSION_HEADER_IFO indicating if        a header extension and/or stuffing byte are/is present; and    -   identifier SERVICE_ID of a service which generated the stream of        interest.

FIRST_AP_OFFSET included in the application packet shown in FIG. 10( d)corresponds to first access point 651 included in sector data header 12in FIG. 10( a).

As shown in FIG. 1( g), transport packet d is recorded across twosectors. When the last time stamp or transport packet extends to thenext sector, transport packet connection flag 652 is set at “1”.

In the example shown in FIG. 1( g), the address in data area 22 of thetime stamp head position located after transport packet d which extendsto the next sector is recorded in first access point 651 (expressed inunits of bits).

The first access point value of sector No. 1 (or its correspondingstream pack) shown in FIG. 1( e) can be set to be larger than the sizeof data area 22 (FIG. 1( f)) of sector No. 1. This value indicates thatthe position of a time stamp corresponding to the next packet of apacket recorded in sector No. 1 is present in the next and subsequentsectors.

In an embodiment of the present invention, since a value larger than thesize of data areas 21, 22, and 23 can be designated as the value offirst access point 651, the time stamp head position can be designatedfor a packet having a size larger than the sector size (or stream packsize=2,048 bytes).

For example, assume that one packet is recorded across sector No. 0 tosector No. 2 in the data structure shown in FIG. 1. Furthermore, a timestamp for that packet is recorded at the first position in data area 21of sector No. 0, and a time stamp for the next packet is set at the T-thbit position in a data area of sector No. 2. Such case will be examinedbelow.

In this case, the first access point value of sector No. 0 is “0”, thatof sector No. 1 is “the size of data area 22 of sector No. 1+T”, andthat of sector No. 2 is “T”.

FIG. 11 is a view for explaining another example of time map information252 in an embodiment of the present invention.

This time map information 252 is an example different from time mapinformation 252 in FIGS. 3( h) and (i), and is table information whichdescribes the stream block sizes, stream block time differences, and thenumbers (AP_Ns) of packets in units of stream blocks (first streamblock, second stream block, . . . ).

Assume that the total number of transport packets (or the total numberAP_Ns of application packets) is designated to access (from the STBside) a predetermined frame (picture) using time map information 252 inFIG. 11. Then, the numbers of transport packets (AP_Ns) are summed up(by the disc apparatus side) in turn from the first stream block in FIG.11 to access a stream block at the time when the designated value hasbeen reached.

FIG. 12 is a view for explaining an example of the internal structure ofa sector (a stream pack including an application packet and a streampack including a stuffing packet) that forms a stream block (SOBU).

Stream object (SOB) #A•298 in FIG. 12( d) is made up of a plurality ofstream blocks #1, #2, . . . , as shown in FIGS. 12( c) and (e).

All stream blocks #1, #2, . . . are formed of stream object units (SOBU)each having a 2-ECC block size (=32 sectors=64 k bytes).

In this manner, even when stream block (SOBU) #2 is deleted, an ECCblock of stream block (SOBU) #1 is not influenced by this deletion.

First stream block (SOBU) #1 of SOB#A•298 is made up of sectors No. 0 toNo. 31 (32 sectors/64 k bytes), as shown in FIG. 12( b).

Each sector of stream block (SOBU) #1 has a similar data structure. Forexample, sector No. 0 has a data structure, as shown in FIG. 12( a).

More specifically, sector No. 0 consists of a 2,048-byte (2-Kbytes)stream pack, which is made up of a 14-byte pack header and 2,034-bytestream PES packet.

The stream PES packet is comprised of a 6-byte PES header, 1-bytesubstream ID, and 2,027-byte stream data area.

The stream data area consists of a 9-byte application header,application header extension (option), stuffing byte (option), andapplication packet area.

The application packet area is made up of a group of application packetseach having an application time stamp (ATS) at its head position.

For example, when a transport packet having a 188-byte size is stored asan application packet in the application packet area, approximately 10application packets can be stored in the application packet area.

In stream recording, an application that generates recording contentsmakes stuffing by itself to obviate the need for independent adjustmentof the pack length. For this reason, in stream recording a stream packcan always have a required length (e.g., 2,048 bytes).

The stuffing byte in FIG. 12( a) is used to maintain the predeterminedlength (2,048 bytes) of a stream pack.

The pack header shown in FIG. 12( a) contains pack start codeinformation, SCR base information, SCR extension information, programmaximum rate information, marker bit, pack stuffing length information,and the like, although not shown.

The SCR base consists of 32 bits, and its 32nd bit is zero. As theprogram maximum rate, 10,08 Mbps are used.

The PES header and substream ID shown in FIG. 12( a) have the contentsshown in FIG. 8( c).

The application header in FIG. 12( a) includes version information, thenumber AP_Ns of application packets, time stamp position FIRST_AP_OFFSETof the first application packet, extension header informationEXTENSION_HEADER_IFO, service ID, and the like, as shown in FIG. 10( c).

Note that the version describes the version number of the applicationheader format.

AP_Ns in the application header describes the number of applicationpackets that start within the stream pack of interest. If the streampack of interest stores the first byte of ATS, it is determined that anapplication packet starts in this stream pack.

FIRST_AP_OFFSET describes the time stamp position of the firstapplication packet that starts within the stream packet of interest as arelative value (unit: byte) from the first byte in this stream packet.If no application packet starts within the stream packet,FIRST_AP_OFFSET describes “0”.

EXTENSION_HEADER_IFO describes whether or not an application headerextension and/or stuffing byte are/is present within the stream packetof interest.

If the contents of EXTENSION_HEADER_IFO are 00b, it indicates thatneither the application header extension nor stuffing byte are presentafter the application header.

If the contents of EXTENSION_HEADER_IFO are 10b, it indicates that theapplication header extension is present after the application header,but no stuffing byte is present.

If the contents of EXTENSION_HEADER_IFO are 11b, it indicates that theapplication header extension is present after the application header,and the stuffing byte is also present after the application headerextension.

The contents of EXTENSION_HEADER_IFO are inhibited from assuming 01b.

The stuffing byte (option) before the application packet area isactivated by “EXTENSION_HEADER_IFO=11b”. In this manner, “packingparadox” can be prevented when the number of bytes in the applicationheader extension is contradictory to the number of application packetsthat can be stored in the application packet area.

SERVICE ID describes the ID of a service that generates the stream. Ifthis service is unknown, SERVICE_ID describes 0x0000.

The application packet area in FIG. 12( a) can have the sameconfiguration as that shown in the lower portion in FIG. 22 to bedescribed later (change “packet” in FIG. 22 to read “application packet”in FIG. 12).

That is, a partial application packet is recorded at the head of theapplication packet area, a plurality of pairs of application time stampsATS and application packets are sequentially recorded after the partialapplication packet, and a partial application packet is recorded at theend of the application packet area.

In other words, a partial application packet can be present at the startposition of the application packet area. At the end position of theapplication packet area, a partial application packet or a stuffing areawith the reserved number of bytes can be present.

The application time stamp (ATS) allocated before each applicationpacket consists of 32 bits (4 bytes). This ATS can be divided into twofields, i.e., a basic field and extended field. The basic field iscalled a 90-kHz unit value, and the extended field indicates a lesssignificant value measured at 27 MHz.

In FIG. 12( a), the application header extension can be used to storeinformation which can differ between application packets. Suchinformation is not always required for all applications.

Therefore, the data field of the application header is defined to beable to describe the presence of the application header extension as anoption in the stream data area (in EXTENSION_HEADER_IFO mentionedabove).

Upon recording a stream, the first byte of application time stamp ATS ofthe first application packet must be aligned to the start position ofthe application packet area in the first stream packet at the beginningof stream object SOB.

On the other hand, as for the subsequent stream packet in the SOB, anapplication packet may be segmented (split) at the boundary ofneighboring stream packets.

The partial application packet shown in FIG. 22 or FIGS. 23( f) and (g)to be described later indicates an application packet formed by thissegmentation (split).

The byte offset of the first application time stamp that starts withinthe stream packet and the number of application packets which startwithin that stream packet are described in the application header.

With this format, stuffing before the first application time stamp andafter the last application packet is automatically done in a givenstream packet.

That is, the automatic mechanism allows “the application to makestuffing by itself”. with this automatic stuffing, a stream packet canalways have a required length.

The application header extension (option) consists of a list of entries.The list includes one entry having a 1-byte length corresponding to eachapplication packet that starts within the stream packet of interest. Thebytes of these entries can be used to store information which may differin units of application packets.

Note that the 1-byte application header extension (option) describes1-bit AU_START, 1-bit AU_END, and 2-bit COPYRIGHT.

When AU_START is set at “1”, it indicates that a related applicationpacket includes a random access entry point (start of a random accessunit) within the stream.

When AU_END is set at “1”, it indicates that a related applicationpacket is the last packet of the random access unit.

COPYRIGHT describes the state of the copyright of a related applicationpacket.

The packet structure shown in FIG. 12( a) can be applied to sectorsother than the last sector of SOB#A•298, but cannot always be applied tothe last sector.

For example, when the last sector of SOB#A•298 is sector No. 63 in FIG.12( f), and this sector consists of padding packet 40, as shown in FIG.12( g), the contents of its padding area 38 (FIG. 12( h)) are differentfrom those in FIG. 12( a).

That is, as shown in FIG. 12( i), the stuffing packet as padding packet40 consists of a 14-byte pack header, 6-byte PES header, 1-bytesubstream ID, 9-byte application header, and 2,018-byte applicationpacket area.

In a pack that includes the head of the stuffing packet, thisapplication packet area consists of 4-byte application time stamp ATSand 2,014-byte zero byte data (data having substantially no recordingcontents).

On the other hand, in a pack including the subsequent stuffing packet,this application packet area consists of 2,018-byte zero byte data(without ATS).

When recording is done at very low bit rate, the stuffing byte isrequired to ensure recovery (playback) of time map information (252 inFIG. 3( h); or MAPL in SOBI in FIG. 15 to be described later). Thestuffing packet in FIG. 12( i) is defined as a conceptual unit for thatpurpose.

The objective of this stuffing packet is achieved when each SOBUincludes at least one ATS value as well as the stuffing area.

The following conditions are attached to the stuffing packet:

-   -   One or a plurality of stuffing packets always start from the        application packet area of a pack after a pack including actual        application packet data; and    -   One or a plurality of stuffing packets consist of one 4-byte        ATS, and zero byte data (following ATS) required to stuff the        application data area of the remaining pack of the SOBU of        interest. Assuming that SOBU_SIZ represents the number of        sectors per SOBU, if 0≦n≦SOBU_SIZ−1, the total length of the        stuffing packet is “4+2,014+n×2,018” bytes.

ATS of the stuffing packet is set as follows:

-   -   In an SOBU in which at least one pack includes actual        application packet data, ATS of the stuffing packet is set to be        that of an application packet preceding the stuffing packet; and    -   In an SOBU that does not include any actual application packet,        ATS of the stuffing packet is determined in accordance with the        contents of time map information or the like.

All packs each of which includes the stuffing packet or a portion of thestuffing packet are configured as follows:

-   -   SCR of the pack header is set to be the sum of SCR of the        preceding pack and “2,048×8 bits+10,08 Mbps”;    -   The PES packet header and substream ID are the same as those of        all other PES packets; and    -   In the application header (see FIGS. 10( c) and 10(d)), AP_NS=0,        FIRST_AP_OFFSET=0, EXTENSION_HEADER_IFO=00b, and SERVICE ID=0        (other parameters in the application header are set at zero).

FIG. 13 is a view for explaining the internal data structure ofmanagement information (STREAM.IFO or SR_MANGR.IFO in FIG. 2) of thestreamer.

STREAM.IFO (SR_MANGR.IFO) 105 as management information (navigationdata) shown in FIG. 2 or FIG. 3( e) includes streamer information STRI,as shown in FIG. 13.

This streamer information STRI is comprised of streamer video managerinformation STR_VMGI, stream file information table SFIT, original PGCinformation ORG_PGCI (more generally, PGC information PGCI#i),user-defined PGC information table UD_PGCIT, text data manager TXTDT_MG,and application private data manager APDT_MG, as shown in FIG. 3( f) orFIG. 13.

Streamer video manager STR_VMGI includes video manager informationmanagement information VTSI_MAT that describes management informationwhich pertains to STRI and STR_VMGI, and the like, and a play listsearch pointer table (PL_SRPT) that describes search pointers used tosearch for a play list in the stream, as shown in FIG. 13.

Note that the play list is a list of a portion of a program. With thisplay list, the user can define an arbitrary playback sequence (for thecontents of a program).

Stream file information table SFIT includes all navigation data thatdirectly pertain to the streamer operation. Details of stream fileinformation table SFIT will be explained later with reference to FIG.15.

Original PGC information ORG_PGCI is a portion that describesinformation which pertains to an original PGC (ORG_PGC). ORG_PGCindicates navigation data which describes a program set. ORG_PGC is achain of programs, and includes stream data recorded in a “.SRO” file(SR_TRANS.SRO 106 in FIG. 2) shown in FIG. 2 or FIG. 18 to be describedlater.

Note that the program set indicates the entire recorded contents (allprograms) of information storage medium 201. Upon playing back theprogram set, the same playback order as the recording order of programsis used except for a case wherein an arbitrary program has been edited,and the playback order of original recording has been changed. Thisprogram set corresponds to a data structure called an original PGC(ORG_PGC).

Also, a program is a logical unit of recorded contents, which isrecognized by the user or is defined by the user. A program in theprogram set is made up of one or more original cells. The program isdefined within only the original PGC.

Furthermore, a cell is a data structure indicating a portion of aprogram. A cell in the original PGC is called an “original cell”, and acell in a user-defined PGC (to be described later) is called a“user-defined cell”.

Each program in the program set consists of at least one original cell.A portion of a program in each play list consists of at least oneuser-defined cell.

On the other hand, only a stream cell (SC) is defined in the streamer.Each stream cell looks up a portion of the recorded bitstream. In anembodiment of the present invention, a “cell” means a “stream cell”unless otherwise specified.

Note that a program chain (PGC) is a generic unit. In an original PGC,PGC indicates a chain of programs corresponding to a program set. On theother hand, in a user-defined PGC, PGC indicates a chain of portions ofprograms corresponding to a play list.

A user-defined PGC indicating a chain of portions of programs includesnavigation data alone. A portion of each program looks up stream databelonging to the original PGC.

User-defined PGC information table UD_PGCIT in FIG. 13 can includeuser-defined PGC information table information UD_PGCITI, one or moreuser-defined PGC search pointers UD_PGC_SRP#n, and one or more pieces ofuser-defined PGC information UD_PGCI#n.

User-defined PGC information table information UD_PGCITI includesUD_PGC_SRP_NS indicating the number of user-defined PGC search pointersUD_PGC_SRP, and UD_PGCIT_EA indicating the end address of user-definedPGC information table UD_PGCIT (not shown).

The number of “UD_PGC_SRP”s indicated by UD_PGC_SRP_Ns is the same asthe number of pieces of user-defined PGC information (UD_PGCI), and isalso the same as the number of user-defined PGCs (UD_PGC). The maximumvalue of UD_PGC_SRP_Ns is “99”.

UD_PGCIT_EA describes the end address of UD_PGCIT of interest by therelative number of bytes (F_RBN) from the first byte of that UD_PGCIT.

Note that F_RBN indicates the relative number of bytes from the firstbyte of the defined field, and starts from zero.

PGCI#i that generally expresses original PGC information ORG_PGCI oruser-defined PGC information UD_PGCI in user-defined PGC informationtable UD_PGCIT will be described later with reference to FIG. 14.

Text data manager TXTDT_MG in FIG. 13 is supplementary text information.This TXTDT_MG can be stored in the play list and program together withprimary text information PRM_TXTI shown in FIG. 14.

Application private data manager APDT_MG in FIG. 13 can includeapplication private data manager general information APDT_GI, one ormore APDT search pointers APDT_SRP#n, and one or more APDT areas APDTA#n(not shown).

Note that application private data APDT is a conceptual area that allowsan application device connected to the streamer to store arbitrarynon-real time information (more desired information in addition toreal-time stream data).

FIG. 14 is a view for explaining the internal data structure of PGCInformation (ORG_PGCI/UD_PGCIT in FIG. 3 or PGCI#i in FIG. 13).

PGC information PGCI#i in FIG. 14 generally expresses original PGCinformation ORG_PGCI or user-defined PGC information UD_PGCI inuser-defined PGC information table UD_PGCIT in FIG. 13.

As shown in FIG. 14, PGC information PGCI#i is made up of PGC generalinformation PGC_GI, one or more pieces of program information PGI#m, oneor more stream cell information search pointers SCI_SRP#n, and one ormore pieces of stream cell information SCI#n.

PGC general information PGC_GI includes the number PG_Ns of programs,and the number SCI_SRP_Ns of stream cell information search pointersSCI_SRP.

Each program information PGI (e.g., PGI#1) includes program type PG_TY,the number C_Ns of cells in the program of interest, primary textinformation PRM_TXTI of the program of interest, and search pointernumber IT_TXT_SRPN of item text.

Note that program type PG_TY includes information indicating the stateof the program of interest. Especially, program type PG_TY includes aflag indicating if that program is protected from an erase error, i.e.,a protect flag.

When this protect flag is “0b”, the program of interest is notprotected; when it is “1b”, the program is protected.

The number C_Ns of cells indicates the number of cells in the program ofinterest. In all the programs and cells in a PGC, cells (tacitly) appendthemselves to each program in their ascending order.

For example, if program #1 in a given PGC has C_Ns=1, and program #2 hasC_Ns=2, first stream cell information SCI of that PGC is appended toprogram #1, and the second SCI and third SCI are appended to program #2.

Primary text information PRM_TXTI describes text information having asingle common character set (ISO/IEC646:1983 (ASCII code)) to allow useof information storage medium (DVD-RAM disc) 201 anywhere in the world.

Item text search pointer number IT_TXT_SRPN describes a search pointernumber corresponding to item text (text data corresponding to theprogram of interest) IT_TXT. If the program of interest has no itemtext, IT TXT SRPN is set at “0000h”.

Each stream cell information search pointer SCI _SRP (e.g., SCI _SRP#1)includes SCI_SA indicating the start address of corresponding streamcell information SCI. This SCI_SA is described as the relative number ofbytes (F_RBN) from the first byte of PGCI.

Each stream cell information SCI (e.g., SCI#1) is made up of stream cellgeneral information SC_GI and one or more pieces of stream cell entrypoint information SC_EPI#n.

Stream cell general information SC_GI includes cell type C_TY includingflag TE indicating a temporary erase (TE) state, the number SC_EPI_Ns ofpieces of entry point information of a stream cell, stream object numberSOB_N, stream cell start APAT (SC_S_APAT shown in FIG. 6 and the like),stream cell end APAT (SC_E_APAT shown in FIG. 6 and the like), erasestart APAT (ERA_S_APAT shown in FIG. 6 and the like) indicating startAPAT of a temporary erase cell if that cell is in the temporary erasestate (TE=01b), and erase end APAT (ERA_E_APAT shown in FIG. 6 and thelike) indicating end APAT of a temporary erase cell if that cell is inthe temporary erase state (TE=10b).

Cell type C_TY describes the type and temporary erase state of thestream cell of interest.

More specifically, cell type C_TY1=“010b” is described in the type ofall stream cells (with this C_TY1=“010b”, a stream cell can bedistinguished from other cells).

On the other hand, if flag TE is “00b”, it indicates that the cell ofinterest is in a normal state; if flag TE is “01b” or “10b”, that cellis in a temporary erase state.

Flag TE=“01b” indicates that the cell of interest (cell in the temporaryerase state) starts from a position after the first application packetthat starts within a SOBU, and comes to an end at a position before thelast application packet in that SOBU.

On the other hand, flag TE=“10b” indicates that the cell of interest(cell in the temporary erase state) includes at least one SOBU boundary(the first or last application packets starts within that SOBU).

Note that a protect flag of a program and TE flag of a cell in thatprogram cannot be set at the same time. Therefore,

(a) none of cells in a program in the protect state can be set in thetemporary erase state; and

(b) a program including one or more cells in the temporary erase statecannot be set in the protect state.

The number SC_EPI_Ns of pieces of entry point information of a streamcell describes the number of pieces of stream cell entry pointinformation included in stream cell information SCI of interest.

Each stream cell entry point information SC_EPI (e.g., SC_EPI#1) in FIG.14 includes two types (types A and B).

SC_EPI of type A includes entry point type EP_TY and entry pointapplication packet arrival time EP_APAT. Type A is set by entry pointtype EP_TY1 “00b”.

SC_EPI of type B includes primary text information PRM_TXTI in additionto EP_TY and EP_APAT of type A. Type B is indicated by entry point typeEP_TY1=“01b”.

As a tool for skipping a portion of the recorded contents in anarbitrary stream cell, an entry point can be used. All entry points canbe specified by application packet arrival times (APAT). This APAT canspecify the data output start position.

Stream object number SOB_N describes the number of an SOB that the cellof interest looks up.

Stream cell start APAT (SC_S_APAT) describes start APAT of the cell ofinterest.

Stream cell end APAT (SC_E_APAT) describes end APAT of the cell ofinterest.

Erase start APAT (ERA_S_APAT) describes an arrival time (APAT) of thefirst application packet that starts within the first SOBU, the headposition of which is included in a given temporary erase cell (TE fieldof its C_TY is “10b”) including at least one SOBU boundary, in thattemporary erase cell.

Erase end APAT (ERA_E_APAT) describes an arrival time (APAT) of thefirst application packet that starts within an SOBU including anapplication packet which immediately follows a temporary erase cell (TEfield of its C_TY is “10b”) including at least one SOBU boundary, inthat temporary erase cell.

FIG. 15 is a view for explaining the internal data structure of thestream file information table (SFIT).

As shown in FIG. 15, stream file information table SFIT is made up ofstream file information table information SFITI, one or more pieces ofstream object stream information SOB_STI#n, and stream file informationSFI.

Stream file information table information SFITI consists of the numberSFI_Ns of pieces of stream file information on information storagemedium (DVD-RAM disc) 201, the number SOB_STI_Ns of pieces of streamobject stream information that follow SFITI, end address SFIT_EA ofSFIT, and start address SFI_SA of SFI.

SFIT_EA describes the end address of SFIT by the relative number ofbytes (F_RBN) from the first byte of SFIT.

SFI_SA describes the start address of SFI by the relative number ofbytes (F_RBN) from the first byte of SFIT.

Stream object stream information SOB_STI includes three differentparameters. Each parameter can assume a value unique to individualbitstream recording. However, these parameter sets can have equal valuesin most bitstream recording. Therefore, SOB_STI is stored in a tableindependently from the table of stream object information (SOBI), andsome stream objects (SOB) are allowed to share identical SOB_STI (i.e.,point to identical SOB_STI). Therefore, the number of pieces of SOB_STIis generally larger than the number of SOBs.

Each stream object stream information SOB_STI (e.g., SOB_STI#1) in FIG.15 includes application packet size AP_SIZ, the number SERV_ID_Ns ofservice IDs, service ID (SERV_IDs), and application packet device unitID (AP_DEV_UID).

AP_SIZ describes the application packet size by the byte length of apacket in a bitstream transferred from an application device to thestreamer.

In the DVD streamer, the application packet size is constant in eachbitstream recording. For this reason, if the application packet sizechanges in each recording free from any interrupt, the current streamobject (current SOB) comes to an end there, and a new stream object (newSOB) starts with new AP_SIZ. In this case, the current and new SOBsbelong to an identical program in original PGC information (ORG_PGCI).

SERV_ID_Ns describes the number of service IDs included in thesubsequent parameter.

SERV_IDs describes a list of service IDs in an arbitrary order.

AP_DEV_UID describes a unique device ID unique to an application devicethat supplies the recorded bitstream.

As shown in FIG. 15, stream file information SFI is comprised of streamfile general information SF_GI, one or more stream object information(SOB information) search pointers (SOB_SRP) #n, and one or more piecesof SOB information (SOBI) #n.

Stream file general information SF_GI includes the number SOBI_Ns ofpieces of SOBI, sector size SOBU_SIZ per SOBU, and MTU_SHFT as a kind oftime map information.

SOBU_SIZ describes the SOBU size using the number of sectors, and thissize is constant to be 32 (32 sectors=64 k bytes). This means that thefirst entry is associated with an application packet included in thefirst 32 sectors of an SOB. Likewise, the second entry is associatedwith an application packet included in the next 32 sectors. The sameapplies to the third and subsequent entries.

Each SOB information search pointer (e.g., SOBI_SRP#1) includes startaddress SOBI_SA of SOBI. This SOBI_SA describes the start address of theassociated SOBI using the relative number of bytes (F_RBN) from thefirst byte of stream file information SFI.

Each SOB information (e.g., SOBI#1) is made up of stream object generalinformation SOB_GI, time map information MAPL, and access unit data AUD(option).

Stream object general information SOB_GI includes stream object typeSOB_TY, stream object recording time SOB_REC_TM, stream object streaminformation number SOB_STI_N, access unit data flag AUD_FLAGS, streamobject start application packet arrival time SOB_S_APAT, stream objectend application packet arrival time SOB_E_APAT, start stream object unitSOB_S_SOBU of the stream object of interest, and the number MAPL_ENT_NSof entries in time map information.

Stream object type SOB_TY is a field that describes bits indicating thetemporary erase state (TE state) and/or bits of the copy generationmanagement system.

Stream object recording time SOB_REC_TM describes the recording time ofthe associated stream object (SOB).

Stream object stream information number SOB_STI_N describes an index ofvalid SOB_STI for the stream object of interest.

Access unit data flag AUD_FLAGS describes whether or not access unitdata (AUD) is present for the stream object of interest, and the type ofaccess unit data if it is present.

If access unit data (AUD) is present, AUD_FLAGS describes someproperties of AUD.

The access unit data (AUD) itself consists of access unit generalinformation AU_GI, access unit end map AUEM, and playback time stamplist PTSL, as shown in FIG. 15.

Access unit general information AU_GI includes AU_Ns indicating thenumber of access units described in correspondence with the SOB ofinterest, and access unit start map AUSM indicating an SOBU that belongsto the SOB of interest and includes an access unit.

Access unit end map AUEM is a bit array having the same length as thatof AUSM (if it is present), and indicates an SOBU that includes theterminal end of a bitstream segment appended to the access unit of theSOB of interest.

Playback time stamp list PTSL is a list of playback time stamps of allaccess units that belong to the SOB of interest. One PTSL elementincluded in this list includes a playback time stamp (PTS) of thecorresponding access unit.

Note that the access unit (AU) indicates an arbitrary single, continuousportion of the recorded bitstream, and is suitable for individualplayback. For example, in an audio/video bitstream, an access unitcorresponds to I-picture of MPEG.

The contents of SOB_GI will be explained again.

AUD_FLAGS includes flag RTAU_FLG, flag AUD_FLG, flag AUEM_FLG, and flagPTSL_FLG.

When flag RTAU_FLG is 0b, it indicates that no access unit flag ispresent in real-time data of the SOB of interest.

When flag RTAU_FLG is 1b, it indicates that AU flags (AU_START, AU_END)described in the application header extension shown in FIG. 9( a) orFIG. 12( a) can be present in real-time data of the SOB of interest.This state is also allowed when AUD_FLG (to be described below) is 0b.

When flag AUD_FLG is 0b, it indicates that no access unit data (AUD) ispresent for the SOB of interest.

When flag AUD_FLG is 1b, it indicates that access unit data (AUD) can bepresent for the SOB of interest.

When flag AUEM_FLG is 0b, it indicates that no AUEM is present in theSOB of interest.

When flag AUEM_FLG is 1b, it indicates that AUEM is present in the SOBof interest.

When flag PTSL_FLG is 0b, it indicates that no PTSL is present in theSOB of interest.

When flag PTSL_FLG is 1b, it indicates that PTSL is present in the SOBof interest.

SOB_S_APAT describes the start application packet arrival time of astream object. That is, SOB_S_APAT indicates the arrival time of thefirst application packet that belongs to the SOB of interest.

This packet arrival time (PAT) is divided into two fields, i.e., a basicfield and extended field. The basic field is called a 90-kHz unit value,and the extended field indicates a less significant value measured at 27MHz.

SOB_E_APAT describes the end application packet arrival time of a streamobject. That is, SOB_E_APAT indicates the arrival time of the lastapplication packet that belongs to the SOB of interest.

SOB_S_SOBU describes the start stream object unit of the stream objectof interest. That is, SOB_S_SOBU indicates an SOBU including the startportion of the start application packet of the stream object.

MAPL_ENT_Ns describes the number of entries in time map information(MAPL) that follows SOBI_GI.

Time map information MAPL has contents corresponding to time mapinformation 252 shown in FIG. 3( h).

One of relevancies between the contents of FIGS. 13 and 15 is summarizedas follows:

Streamer information STRI included in management information 105contains stream file information table SFIT that manages stream objectSOB which forms the contents of stream data. This SFIT includes streamobject information SOBI that manages SOB. This SOBI includes access unitgeneral information AU_GI including management information (access unitstart map AUSM), and management information (PTSL).

Note that the management information (ATS or AUSM) contains informationused upon transferring stream data, and the management information (PTSor SC_S_APAT) contains information used when the stream data isdisplayed.

FIG. 16 is a view exemplifying the correspondence between the accessunit start map (AUSM; see FIG. 15) and stream object unit (SOBU; seeFIG. 1, FIGS. 4 to 6, and FIG. 12).

As shown in FIG. 16, bit “1” of AUSM indicates that the access unit (AU)is included in the corresponding SOBU.

Assume that AUSM_pos(i) represents the i-th (1≦i≦AU_Ns) bit positionwhere a bit is set in AUSM. Then, the position of access unit AU is asfollows.

(1) If SOBU#i indicated by AUSM_pos(i) contains one or more start AUs(described using AU_START and AU_END marks in a stream (if available)),AUSM_pos(i) is assigned to the first AU that starts within SOBU#i. Notethat SOBU#i is laid out in SOBUS described using AUSM_pos(i) andAUEM_pos(i) (if AUEM is available).

(2) AU comes to an end at the AU_END mark that appears first after thisAU starts, and comes to an end in the last SOBU indicated by theassigned AUEM element (if AUEM is available).

In any access unit data, two or more accessible access units cannot bedescribed per SOBU in an SOB.

FIG. 17 is a view exemplifying the correspondence between the accessunit start map (AUSM; see FIG. 15) and access unit end map (AUEM; seeFIG. 15), and stream object unit (SOBU; see FIGS. 2, 4, and 11).

AUEM is a bit array having the same length as the AUSM (if available).The bits of AUEM indicate a SOBU that includes the end of a bitstreamsegment appended to the access unit of the SOB of interest.

The number of bits set in AUEM matches that set in AUSM. That is, theset bits in AUSM have those set in AUEM in correspondence with eachother.

Assume that AUSM_pos(i) represents the i-th (1≦i≦AU_NS) bit positionwhere a bit is set in AUSM, and AUEM_pos(i) the i-th (1≦i≦AU_Ns) bitposition where a bit is set in AUEM. In this case, the followingrelations hold:

(1) 1≦AUSM_pos(i)≦AUEM_pos(i)≦MAPL_ENT_Ns;

(2) AUSM_pos(i+1)>AUEM_pos(i);

(3) If i==AU_Ns or AUSM_pos(i+1)>1 AUEM_pos(i), AU#i comes to an end inSOBU#[AUEM_pos(i)] (1≦i≦AU_Ns); and

(4) If AUSM_pos(i+1)==1+AUEM_pos(i), AU#i coes to an end inSOBU#[AUEM_pos(i)]. Or it comes to an end at the position ofSOBU#[1+AUEM pos(i)]==SOBU#[AUSM_pos(i+1)]. That is, AU#i comes to anend at the beginning of AU#i+1 in SOBU (1≦i≦AU_Ns).

FIG. 18 is a view showing an example of the relationship defined betweencells designated by an original or user-defined PGC, and SOBUscorresponding to these cells via time map information.

A user-defined PGC does not contain its own SOB, but looks up an SOB inan original PGC. Therefore, the user-defined PGC can be described usingonly PGC information. This means that an arbitrary playback sequence canbe implemented without modifying SOB data.

The user-defined PGC does not contain any program, and is made up of achain of cells corresponding to portions of programs in the originalPGC.

FIG. 18 shows an example of such user-defined PGC. In this example,user-defined PGC#n is formed so that a cell in the PGC looks up an SOBin an original PGC.

Referring to FIG. 18, PGC#n has four cells #1 to #4. Of these cells, twocells look up SOB#1, and the remaining two cells look up SOB#2.

The solid arrows from cells in the user-defined PGC to the original PGC(time map information of an SOBI) indicate the playback periods of thosecells. The cell playback order in the user-defined PGC becomes quitedifferent from that in the original PGC.

Playback of an arbitrary SOB and its SOBUs is specified by start APAT(S_APAT) and end APAT (E_APAT) in FIG. 18.

S_APAT of the SOB or SOBU is defined in association with a time stamprecorded in the payload (see FIG. 1( h), FIG. 22, and FIG. 23) of astream pack of the SOB of interest.

During SOB recording, each incoming application packet is appended witha time stamp by the local clock reference in the streamer. This is theapplication packet arrival time (APAT).

APAT of the start application packet of the SOB is stored as SOB_S_APAT.Four least significant bytes of all APATs are fixed in advance for acorresponding application packet in a “_.SRO” file.

In order to play back data of the SOB or SOBU, the internal referenceclock of the streamer is set at an SCR value, and clocks are thenautomatically counted. This SCR value is described in the first streampack (pack header) from which playback begins. Based on the clocks, allsubsequent application packets are played back and output from the SOBor SOBU.

When an arbitrary stream cell (SC) defines stream cell start APAT(SC_S_APAT) that has an arbitrary value between SOB_S_APAT andSOB_E_APAT of an SOB that SC points to, an address used to find out anSOBU that includes an application packet with a desired APAT isrequired.

The number of stream packs per SOBU is constant, but the intervals ofarrival times captured by SOBUs are flexible. Therefore, each SOB hastime map information (MAPL) that describes the arrival time intervals ofits SOBUs. That is, the address system implemented by time mapinformation (MAPL) converts arbitrary APAT into a relative logical blockaddress in the file to point to an SOBU that can find out a desiredapplication packet.

FIG. 19 is a block diagram for explaining the arrangement of a streamdata recording/playback system (optical disc device/streamer, STB unit)according to an embodiment of the present invention. This embodimentassumes as information storage medium 201 a recordable/reproducibleoptical disc such as a DVD-RAM disc or the like.

The internal structure of the stream data recording/playback apparatusaccording to an embodiment of the present invention will be describedbelow using FIG. 19.

This stream data recording/playback apparatus comprises optical discdevice (or optical disc drive) 415, STB unit (or STB device) 416, andtheir peripheral devices.

The peripheral devices include video mixing unit 405, frame memory 406,external loudspeaker 433, personal computer (PC) 435, monitor TV 437,D/A converters 432 and 436, I/F units 431 and 434, and the like.

Optical disc device 415 comprises recording/playback unit 409 includinga disc drive, data processor (to be abbreviated as D-PRO hereinafter)410 for processing stream data to recording/playback unit 409 (or streamdata from recording/playback unit 409), temporary storage 411 fortemporarily storing stream data that overflows from D-PRO 410, andoptical disc device controller 412 for controlling operations ofrecording/playback unit 409 and D-PRO 410.

Optical disc device 415 further comprises data transfer interface 414for receiving stream data sent from STB unit 416 via IEEE1394 or thelike (or sending stream data to STB unit 416 via IEEE1394 or the like),and formatter/deformatter 413 for converting the stream data received bydata transfer interface 414 into a signal format that can be recorded oninformation storage medium (RAM disc) 201 (or converting the stream dataplayed back from medium 201 into a signal format for, e.g., IEEE1394 orthe like).

More specifically, the IEEE1394 reception side of data transferinterface 414 reads the time from the start of stream data transfer onthe basis of the time count value of reference clock generator (systemtime counter STC) 440.

Based on the time information, delimiter information for dividing streamdata in units of stream blocks (or in units of SOBUs) is generated, andcell division information, program division information, and PGCdivision information are generated in correspondence with this delimiterinformation.

Formatter/deformatter 413 converts the stream data sent from STB unit416 into a stream pack sequence (see FIG. 12( a), FIG. 23( h), etc.),and inputs the converted stream pack sequence to D-PRO 410. Each of theinput stream packs has a constant size of 2,048 bytes, which is equal tothe sector size. D-PRO 410 combines the input stream packs in units of16 sectors to form ECC blocks, and sends the ECC blocks torecording/playback unit 409.

When recording/playback unit 409 is not ready to record data on medium201, D-PRO 410 transfers recording data to temporary storage 411 totemporarily save them therein, and waits until recording/playback unit409 is ready to record data.

When recording/playback unit 409 is ready to record data, D-PRO 410transfers data saved in temporary storage 411 to recording/playback unit409. In this manner, recording on medium 201 is started. Upon completionof recording of data saved in temporary storage 411, the subsequent dataare seamlessly transferred from formatter/deformatter 413 to D-PRO 410.

Assume that a large-size memory is used as temporary storage 411 so asto store recording data for several minutes or more by high-speedaccess.

Note that time stamp information appended to the recording bitstream viaformatter/deformatter 413 can be obtained from reference clock generator(STC) 440.

On the other hand, time stamp information (SCR) extracted from theplayback bitstream via formatter/deformatter 413 can be set in STC 440.

Each pack header in the stream data recorded on information storagemedium 201 records a reference clock (system clock reference SCR). Whenthe stream data (SOB or SOBU) recorded on this medium 201 is playedback, reference clock generator (STC) 440 is adjusted to the referenceclock (SCR) played back from medium 201 (the SCR value is set in STC440).

That is, in order to play back SOB or SOBU data, the reference clock(STC 440) in the streamer (optical disc device 415) is adjusted tosystem clock reference SCR described in the first stream pack from whichplayback starts. After that, STC 440 is automatically counted up.

STB unit 416 comprises demodulator 422 for demodulating the contents ofa digital broadcast wave received by satellite antenna 421, andproviding demodulated data (stream data) that multiplexes one or moreprograms, and reception information selector 423 for selectinginformation of a specific program (of user's choice) (taking FIG. 23 tobe described later as an example, a transport packet of program 2) fromdata demodulated by demodulator 422.

When the information (transport packet) of the specific program selectedby reception information selector 423 is to be recorded on informationstorage medium 201, selector 423 sends stream data containing only thetransport packet of the specific program to data transfer interface 414of optical disc device 415 by IEEE1394 transfer via data transferinterface 420 in accordance with an instruction from STB controller 404.

When the user merely reviews the information (transport packet) of thespecific program selected by reception information selector 423 withoutrecording it, selector 423 sends stream data containing only thetransport packet of the specific program to multiplexed informationdemultiplexer 425 of decoder unit 402 in accordance with an instructionfrom STB controller 404.

On the other hand, when a program recorded on information storage medium201 is to be played back, stream data sent from optical disc device 415to STB unit 416 via an IEEE1394 serial bus is sent to multiplexedinformation demultiplexer 425 of decoder unit 402 via selector 423.

Multiplexed information demultiplexer 425 classifies various packets(video packets, audio packets, and sub-picture packets) contained in thestream data sent from selector 423 on internal memory 426 on the basisof their IDs. Then, demultiplexer 425 distributes the classified packetsto corresponding decoders (video decoder 428, sub-picture decoder 429,and audio decoder 430).

Video decoder 428 decodes (MPEG-encoded) video packets sent frommultiplexed information demultiplexer 425 to generate moving picturedata. Video decoder 428 incorporates representative image (thumbnail)generator 439 to provide a function of generating a reduced-scalepicture (thumbnail picture) that represents the recorded contents fromI-picture in MPEG video data in such case.

Moving picture data (and/or the representative image generated bygenerator 439) decoded by video decoder 428, sub-picture data(information of superimposed dialogs, menus, and the like) decoded bysub-picture decoder 429, and audio data decoded by audio decoder 430 aresent to video mixing unit 405 via video processor 438.

Video mixing unit 405 generates a digital video by superposing thesuperimposed dialogs and the like on the moving picture using framememory 406. This digital video is converted into an analog video via D/Aconverter 436, and the analog video is sent to monitor TV 437.

Also, the digital video from video mixing unit 405 is fetched as neededby personal computer 435 via I/F unit 434 and a signal line such asIEEE1394 or the like.

On the other hand, digital audio information decoded by audio decoder430 is sent to external loudspeaker 433 via D/A converter 432 and anaudio amplifier (not shown). Also, decoded audio information isdigitally output to an external device via I/F unit 431.

Note that the operation timing in STB unit 416 is determined by clocksfrom system time counter (STC) 424.

The aforementioned instructions and the like from STB controller 404(operation control of the internal components of STB unit 416) areexecuted by a control program stored in program memory 404 a. In thiscase, work memory 407 is used as needed in the control process of STBcontroller 404.

The internal operation timings of STB unit 416 including STB controller404 and decoder unit 402 can be restricted by clocks from STC unit 424.By synchronizing STC 440 of optical disc device 415 with STC unit 424 ofSTB unit 416, the operation timings of the overall streamer systemincluding optical disc device 415 and STB unit 416 can be restricted.

As a method of synchronizing STC 440 with STC unit 424, a method ofsetting STC 440 and STC unit 424 using a reference clock (SCR) in streamdata exchanged between data transfer interfaces 414 and 420 isavailable.

The device arrangement in STB unit 416 shown in FIG. 19 can befunctionally divided/categorized into a “reception time managementmodule”, “stream data content analysis module”, “stream data transfermodule”, and “time related information generation module”.

Note that the “reception time management module” is comprised ofdemodulator (demodulation unit) 422, reception information selector 423,multiplexed information demultiplexer 425, STB controller 404, and thelike. The “reception time management module” receives digital TVbroadcast via satellite antenna 421, and records reception times inunits of transport packets in the received broadcast information.

The “stream data content analysis module” is comprised of multiplexedinformation demultiplexer 425, STB controller 404, and the like. This“stream data content analysis module” analyzes the contents of thereceived stream data, and extracts I-, B-, and P-picture positionsand/or PTS values.

The “stream data transfer module” is comprised of multiplexedinformation demultiplexer 425, reception information selector 423, STBcontroller 404, data transfer interface 420, and the like. This “streamdata transfer module” transfers the stream data to optical disc device415 while holding differential reception time intervals in units oftransport packets.

The “time related information generation module” is comprised ofmultiplexed information demultiplexer 425, STB controller 404, datatransfer interface 420, and the like. The “time related informationgeneration module” generates relationship information between receptiontime (time stamp) information recorded by the “reception time managementmodule” and display time information (PTS value and/or the number offields) extracted by the “stream data content analysis module”.

FIG. 20 is a view for explaining the time relationship table thatindicates the relationship between the display time and data transfertime in an embodiment of the present invention. A basic feature of thisinvention will be explained below using FIG. 20.

The NTSC scheme as one of TV display schemes displays 30 images/pictures(frames) on a TV monitor screen as a video signal. Since a normal TVuses interlaced scan, an image is scanned every other lines of all scanlines for one image, and is then scanned remaining, every other lines tofill gaps of the immediately preceding image, thus displaying one image(picture). The image to be displayed every other lines is called afield.

The NTSC scheme displays 30 frames/60 fields per sec. The NTSC scheme isa display scheme mainly adopted in Japan and USA. By contrast, the PALscheme adopted in Europe displays 25 frames/50 fields per sec.

FIG. 20( a) is a view showing 30 changing images/pictures (frames) persec which are aligned along the display time (presentation time; orplayback time) 1.

As information that expresses display time (playback time) 1 of animage/picture,

(a) a method of expressing time by “the number of differential fieldsfrom a specific image (picture)”; and

(b) a method of expressing time by “PTS (presentation time stamp; orplayback time stamp)” are available.

PTS can be used in the method of expressing the display time by thevalue of a counter which always increments (the counter value increasesin unitary increments) using reference clocks of 27 MHz and/or 90 kHz.For example, the value of a counter when each image/picture (frame) isindicated by a counter which increments using reference clocks of 27 MHz(or 90 kHz) is used as the PTS value.

In reception signal information in digital TV, picture headerinformation 41 (see FIG. 1( j)) contains PTS values in units ofpictures.

In FIG. 20( a), the display time of I-picture a is represented by PTSNo. 1, and the display times of I-pictures i and q are represented byPTS No. 2 and PTS No. 3.

Assume that the user instructs to display an image (picture) xx hours yyminutes zz seconds after display of I-picture a. Then, the designatedtime interval (xx hours yy minutes zz seconds after) is converted into acount value of 27 MHz and/or 90 kHz. The sum of this converted value andthe PTS value (PTS No. 1) of display of I-picture a is then computed toreach the “image (picture) to be displayed” designated by the user.

Since stream data is recorded on information storage medium 201 whilebeing appended with time stamps in units of transport packets, as shownin FIG. 1( g) and the like, time management for the stream data is doneusing this time stamp information.

However, since this time stamp information is invisible to the user, theuser designates the image (picture) of his or her choice using displaytime (playback time) 1.

In this case, information indicating the relationship between the timestamp information used to manage the stream data, and display time(playback time) 1 information that the user can designate is required.The information indicating this relationship is time relationship table2 shown in FIG. 20( b) (or playback time stamp list PTSL in FIG. 15).

As exemplified in FIG. 20( b), time relationship table 2 describescorresponding data transfer time information (I-picture transfer starttime 4), data transfer time information (I-picture transfer end time 5),and the total number 10 of packets from the beginning of a cell to atarget I-picture in units of PTS values (PTS No. 1, PTS No. 2, PTS No.3, . . . ).

For example, as for I-picture a of PTS No. 1, time stamp (ATS) #1 in therow of data transfer time information (I-picture transfer start time 4)corresponds to time stamp (ATS) #1 of head-side packet (AP) #1 ofI-picture a information 7 in FIG. 2( c), and time stamp (ATS) #2 in therow of data transfer time information (I-picture transfer end time 5)corresponds to time stamp (ATS) #2• of trailing-side packet (AP) ofI-picture a information 7 in FIG. 2( c). In this case, since I-picture ais the first one, the total number 10 of packets for I-picture a of PTSNo. 1 is “1”, as shown in FIG. 20( b).

Likewise, as for I-picture i of PTS No. 2, time stamp (ATS) #3 in therow of data transfer time information (I-picture transfer start time 4)corresponds to time stamp (ATS) #3 of head-side packet (AP) #1 ofI-picture i information 8 in FIG. 2( c), and time stamp (ATS) #4 in therow of data transfer time information (I-picture transfer end time 5)corresponds to time stamp (ATS) #4 of trailing-side packet (AP) ofI-picture i information 8 in FIG. 2( c). In this case, since I-picture iappears 85,100 images after the first I-picture a, the total number 10of packets for I-picture i of PTS No. 2 is “85101”, as shown in FIG. 20(b). The same applies to PTS No. 3 and the subsequent PTS values.

A characteristic feature of the present invention lies in that timerelationship table 2 shown in FIG. 20( b) is recorded in an area wheremanagement information (SFIT in FIG. 15) that pertains to stream data(STREAM.VRO 106 in FIG. 1( c), FIG. 20( c), and the like) is recorded,and the user can designate an image position in units of pictures usingthis time relationship table.

The correspondence between time relationship table 2 and playback timestamp list PTSL shown in FIG. 15 will be explained below.

If ATS represents a time stamp shown in FIG. 1( g) and the like, the PTSvalue included in playback time stamp list PTSL in FIG. 15 and ATS havethe following relationship:

(1) a cell looks up a portion of the recorded bitstream;

(2) AU (normally, I-picture) is a continuous portion of the recordedbitstream (AU corresponds to a portion of a cell);

(3) an SOBU that includes the AU (I-picture corresponding to a portionof a cell) is indicated by access unit start map AUSM in FIG. 15 (seeFIG. 16);

(4) the PTS value is the playback time of the corresponding AU (displaytime; or presentation time PTM) (the PTS value corresponding to the AUcorresponds to a portion of a cell in association with the playbacktime);

(5) cell start APAT (SC_S_APAT) is the arrival time of a transportpacket or application packet of the cell of interest (SC_S_APATcorresponds to the PTS value in association with the playback time);

(6) transport packet or application packet AP includes time stamp ATS atits head position (see FIG. 22, FIG. 29( g), etc.);

(7) the PTS value is included in PTSL (see FIG. 15); and

(8) from (3) to (7), the PTS value included in PTSL corresponds to ATSthrough the mediation of AUSM, SC_S_APAT, and the like.

Therefore, playback time stamp list PTSL can be “time relationship table(FIG. 20( b))” including information (PTS value) indicating therelationship (one which pertains to the playback time) between the starttime (SC_S_APAT) of AU (I-picture) and time stamp ATS of a packetincluded in the bitstream.

Or PTSL (time relationship table) can be information indicating thecorrespondence between the PTS value and ATS.

Display of B- or P-picture must be started from display (decode) ofI-picture. For this reason, time relationship table 2 shown in FIG. 20(b) represents a list of display time information corresponding to a timestamp at the I-picture position.

In this case, as the display time information, “PTS information (PTSvalue)”, “the number of differential fields from a specific referenceimage (picture)”, “date & time information”, and the like can be used.

Note that the differential information between I-pictures (e.g.,information indicating the number of fields inserted between I-pictures)may be used as the time display information in place of the absolutevalue display shown in FIG. 20( b). (A time relationship table that usesthe number of fields will be explained later with reference to FIG. 28).

In FIG. 20( b), “PTS information” is used as the display timeinformation. However, the embodiment of the present invention thatallows various modifications is not limited to this specific method, and“the number of differential fields from a specific reference image(picture)”, “date & time information”, or the like can be used instead.

Time relationship table 2 shown in FIG. 20( b) records not only thevalues of transfer start time 4 in units of I-pictures in a list as timestamps (ATS) #1, #3, and #5, but also the values of transfer end time 5in units of I-pictures as time stamps (ATS) #2, #4, and #6.

For this reason, upon making special playback such as fastforward (FF)playback, fast reverse (FR) playback, or the like, the transport packetposition (or application packet position) of I-picture to be played backcan be designated like “from time stamp (ATS) #1 to #2”, “from timestamp (ATS) #3 to #4”, “from time stamp (ATS) #5 to #6”, and so forth.By so doing, only I-picture information (or access unit AU information)can be played back from information storage medium 201, so that theplayed back information is decoded and displayed.

In the embodiment shown in FIG. 20( a), the display start pictureposition (the position of B-picture i) of an original cell (see FIG. 4)is used as a reference. The difference between the PTS value (PTS No. 5)of the display start picture of this original cell and that (PTS No. 1)of I-picture a immediately before that picture is PTS offset 9. This PTSoffset value 9 is recorded in original cell information 272, as shown inFIG. 3( h).

More specifically, as shown in FIG. 20( a), assume that the displaystart picture of the original cell is B-picture f, and the PTS value atthat time is PTS No. 5. If the display time of I-picture a immediatelybefore that picture is PTS No. 1, the value of PTS offset 9 is given by“PTS No. 5−PTS No. 1”.

When the user designates a specific image (specific picture frame), heor she normally designates it using the differential display time fromthe display start position of the original cell. By converting thisdifferential display time into a counter value of 27 MHz and/or 90 kHz,the PTS value of the image (picture frame) designated by the user can becomputed.

As shown in FIG. 20( b), time relationship table 2 records a PTS valuelist in units of I-pictures. By searching for the PTS value of anI-picture position, which is smaller than and closest to the computedPTS value with reference to this table, and designating the time stamp(ATS) value of corresponding I-picture transfer start time 4 there,access to information storage medium 201 is started.

As shown in FIG. 20( b), time relationship table 2 also records thetotal number 10 of transport packets (access position information) fromthe head position of the original cell to the corresponding I-pictureparallel to time stamps.

Hence, according to the embodiment shown in FIG. 20, a desired streamdata position can be also be accessed by designating the number oftransport packets from the head position of the original cell (or thenumber AP_Ns of application packets) in place of the time stamp (ATS).

When stream data (STREAM.VRO) 106 shown in FIG. 20( c) is recorded oninformation storage medium 201 shown in FIG. 3 and the like, thecontents (SOB or SOBU) of stream data 106 are recorded on a data area(STREAM.VRO/SR_TRANS.SRO) of medium 201 in predetermined data recordingunits (transport packets or application packets). In this case,management information (STRI) that pertains to stream data 106 is alsorecorded on a management area (STREAM.IFO/SR_MANGR.IFO) of medium 201.

This management information (STRI) records first management information(ATS corresponding to the I-picture transfer start time; or AUSM) usedto access stream data 106 (access I-picture information or access unitAU); and third management information (time relationship table; or PTSL)which is different from the first management information (AUSM) andindicates the relationship between the first management information andsecond management information (PTS; or SC_S_APAT) used to access thefirst management information and the stream data.

Stream data 106 is a bitstream compressed based on MPEG, and the secondmanagement information corresponds to the playback time (PTS) of thestream data.

FIG. 21 is a view for explaining the relationship between the displaytime and data transfer time in an embodiment of the present invention.

The layout relationship between the recording positions of pictureinformation 6010 to 6030 and stream blocks (SOBUs) in association withthe data structure in stream data (STREAM.VRO 106 in FIGS. 1, 2, etc.)recorded on information storage medium 201 will be explained using FIG.21.

In this embodiment, stream data is recorded in units of stream blocks(SOBUs), and access to a predetermined image (picture) is designatedusing time stamp information.

When STB unit 416 in FIG. 19 designates a time stamp value as theplayback start position, information used to compute a stream block(SOBU) corresponding to the designated time stamp value is time mapinformation 252 in FIG. 3( h) (or time map information MAPL in FIG. 15or time map information in FIG. 18).

In the example in FIG. 3( h), time map information 252 is recorded as aportion of stream object information (SOBI) 242 in STREAM.IFO 105 as themanagement information recording area for stream data. In the example inFIG. 15 as well, time map information MAPL is recorded as a portion ofSOBI.

Time map information 252 shown in FIG. 3( i) records only time stampdifferential time information of each stream block. In this case, thevalues of time differences 263 and 265 of stream blocks in time mapinformation 252 are summed up in each of stream object information(SOBI) 242 or 243. Comparison must be made to check if this summed-upvalue has reached the time stamp time designated by STB unit 416. Basedon the comparison result, the position of a stream block (SOBU) in astream object (SOB), which block includes the time stamp value thatmatches the time designated by STB unit 416, is detected.

As shown in FIG. 21( c), the boundary position of each of pictureinformation 6010 to 6030 does not always match that of a stream block(SOBU).

In this case, as shown in, e.g., FIG. 21( a), if playback is to bestarted from the position of P-picture o with the PTS value=PTS No. 6,the following process is required.

More specifically, the value of PTS No. 2 of I-picture i immediatelybefore that picture is detected from time relationship table 2 (theinternal structure is the same as that shown in FIG. 20( b)) in FIG. 21(b), and playback must be started from the head position of stream block(SOBU) #A that includes first transport packet #2 in which I-pictureinformation 6010 is recorded.

In this case, before playback progresses from the head position ofstream block (SOBU) #A to the position of desired P-picture o, pictureinformation during that period (pictures i to n in FIG. 21( a)) is notoutput to the external monitor (TV).

FIG. 22 is a view for explaining the relationship between the videoinformation compression method in MPEG and transport packets, and therelationship between transport packets in MPEG and application packetsin the streamer.

AS shown in FIG. 22, broadcast signal information in digital TV adopts asignal compression method called MPEG2. In the signal compression methodbased on MPEG, images (pictures) for TV display are categorized intoI-picture 551 that does not contain any time differential information,and B-pictures 553 and 554 and P-picture 552 which contain timedifferential information.

I-picture independently exists without being influenced by the previousor next image (picture) information, and after DCT transformation for asingle image (picture), quantized information becomes I-picturecompressed information 561 and is recorded as I-picture information 31.As for P-picture 552, only differential information 562 from I-picture551 is recorded as P-picture information 32. As for B-pictures 553 and554, two pieces of differential information from I-picture 551 andP-picture 552 are recorded as pieces of B-picture information 33 and 34.

Hence, upon video playback, P-picture 552 and B-pictures 553 and 554cannot solely generate images, but can generate picture images onlyafter the image of I-picture 551 is generated. Pieces of pictureinformation 31 to 34 are divisionally recorded in the payloads of one ora plurality of transport packets. At this time, the information isrecorded so that the boundary position of each of picture information 31to 34 always matches that between neighboring transport packets.

When transport packets in FIG. 22 are recorded by the streamer (opticaldisc device 415 in FIG. 19), the contents of transport packets aretransplanted to packets (application packets) with time stamps calledapplication time stamps (ATS).

A group of application packets with ATS (normally, around 10 packets)are stored in an application packet area in a stream PES packet.

One stream pack is formed by appending a pack header to this stream PESpacket.

The stream PES packet is made up of a PES header, substream ID,application header, application header extension (option), stuffingbytes (option), and application packet area for storing the group ofapplication packets with ATS.

FIG. 23 is a view for explaining the correspondence among the digitalbroadcast contents, the video data transfer format in IEEE1394, andstream packs in the streamer.

In digital broadcast, video information compressed according to MPEG2 istransferred in transport packets. Each transport packet is made up oftransport packet header 511, and payload 512 that records a data mainbody of recording information, as shown in FIG. 23( b).

Transport packet header 511 is comprised of payload unit start indicator501, packet ID (PID) 502, random access indicator 503, program clockreference 504, and the like, as shown in FIG. 23( a).

The MPEG-compressed video information contains I-, B-, and P-pictureinformation. In the first transport packet that records I-pictureinformation, random access indicator 503 in FIG. 23( a) is set withflag=“1”. On the other hand, in the first transport packets of B-pictureinformation and P-picture information, payload unit start indicator 501in FIG. 23( a) is set with flag=“1”.

Using information of these random access indicator 503 and payload unitstart indicator 501, information of an I-picture mapping table (641 inFIG. 9( e)) and information of a B/P-picture start position mappingtable (642 in FIG. 9( e)) are generated.

For example, a bit at the corresponding position in the B/P-picturestart position mapping table (642 in FIG. 9( e)) is set at “1” for atransport packet having payload unit start indicator 501 shown in FIG.23( a) set with flag=“1”.

In digital broadcast, video information and audio information aretransferred in different transport packets. The video information andaudio information are distinguished by packet ID (PID) 502 in FIG. 23(a). Using information of this PID 502, a video packet mapping table (643in FIG. 9( e)) and an audio packet mapping table (644 in FIG. 9( e)) aregenerated.

As shown in FIG. 23( c), a plurality of programs (programs 1 to 3 inthis example) are time-divisionally transferred while being packetizedin a single transponder.

For example, information of transport packet header 511 and that ofpayload (recording information) 512 in FIG. 23( b) are transferred bytransport packets b•522 and e•525 of program 2 shown in FIG. 23( c).

When the user instructs to record, for example, the second program inFIG. 23( c) on information storage medium 201, reception informationselector 423 in STB unit 416 shown in FIG. 19 extracts only transportpackets b and e of program 2.

At that time, STB unit 416 appends reception time information oftransport packets b 522 and e 525 in the form of time stamps 531 and532, as shown in FIG. 23( d).

After that, when data is transferred to formatter/deformatter 413 inFIG. 19 according to the IEEE1394 transfer scheme, the pairs of timestamps and transport packets are transferred while being segmented intosmall units, as shown in FIG. 23( e).

Formatter/deformatter 413 in FIG. 19 temporarily converts stream datatransferred by IEEE1394 from STB unit 416 into the format shown in FIG.23( d) (corresponding to the format shown in FIG. 1( g)). A bitstream inthe format shown in FIG. 23( d) (a stream pack sequence in FIG. 23( h))is recorded on information storage medium 201.

More specifically, in an embodiment of the present invention, packheaders and PES headers which record system clock information and thelike are inserted at the head positions of respective sectors (see FIG.23( h), etc.).

A plurality of time stamps and transport packets (FIG. 1( g)) are packedin data areas 21, 22, and 23 (FIG. 1( f)), and one transport packet(packet d in FIG. 1( g); packet b of program 2 in FIG. 23( d)) isrecorded across a plurality of sectors (Nos. 0 and 1 in FIG. 1( e);partial packets in FIGS. 23( f) and (g)). This is one feature of thepresent invention.

Using the data structure that utilizes this feature, a packet having asize larger than the sector size (e.g., 2,048 bytes) can be recorded.This point will be described in more detail below.

Digital broadcast adopts a multi-program compatiblemultiplexing/demultiplexing scheme called a transport stream, as shownin FIG. 23( c), and one transport packet b•522 often has a size of 188bytes (or 183 bytes).

As described above, one sector size is 2,048 bytes, and each of dataareas 21, 22, and 23 (FIG. 1( f)) can record approximately 10 transportpackets for digital broadcast even after various header sizes aresubtracted.

By contrast, in a digital communication network such as ISDN or thelike, a long packet having a packet size as large as 4,096 bytes isoften transferred.

Using the data structure that utilizes the feature (capable of recordingone packet data across a plurality of packets) so that each of dataareas 21, 22, and 23 (FIG. 1( f)) can record not only a plurality oftransport packets, but also a packet with a large packet size such as along packet, one packet is recorded to extend across a plurality of dataareas 21, 22, and 23.

As a result, all packets, i.e., transport packets for digital broadcast,a long packet for digital communications, and the like can be recordedin a stream block without any fractions independently of their packetsizes.

A normal packet is appended with a time stamp. However, as shown in FIG.23( g), a time stamp can be omitted in a partial packet.

In this manner, partial packets (the partial packet size falls withinthe range from 1 to 187 bytes if the packet size is 188 bytes; anaverage of less than 100 bytes) divided at the boundary of twoneighboring stream packs (FIG. 23( h)) can be effectively used ininformation recording. In addition, the storage capacity of medium 201can be increased by an amount of each time stamp (e.g., 4 bytes per timestamp) omitted from a partial packet.

Note that the position of a time stamp located immediately after thefirst packet in FIG. 23( g) can be specified by first access point 625in FIG. 10( b), or FIRST_AP_OFFSET shown in FIG. 10( c).

Optical disc device 415 (streamer) in FIG. 19 records pairs of timestamps and transport packets (FIGS. 23( f) and (g)) on informationstorage medium 201 without any conversion.

FIG. 24 is a flow chart for explaining the recording sequence of streamdata according to an embodiment of the present invention. The processupon recording stream data will be explained using FIG. 24. This processcan be implemented by a processing program stored in program memory 404a of STB controller 404 shown in FIG. 19.

As shown in FIG. 23( c), a plurality of pieces of program informationare time-divisionally multiplexed in a single transponder.

Reception information selector 423 in FIG. 19 extracts a transportpacket of only a specific program from a packet sequence of theplurality of time-divisionally multiplexed program information (stepS01).

The “reception time management unit (demodulator 422, receptioninformation selector 423, multiplexed information demultiplexer 425, STBcontroller 404 and the like in FIG. 19)” temporarily saves the requiredprogram information in memory 426 of multiplexed informationdemultiplexer 425 (step S02).

At the same time, reception times in units of transport packets aremeasured, and the measurement values are appended to the respectivetransport packets (or application packets) as time stamps (ATS), asshown in FIG. 23( d). Each time stamp information appended in this wayis recorded in memory 426 (step S03).

The “stream data content analysis unit (multiplexed informationdemultiplexer 425, STB controller 404, and the like in FIG. 19)”analyzes information in the transport packets (application packets)recorded in memory 426.

More specifically, each picture boundary position is extracted from thetransport packet (application packet) sequence, and PTS information (orinformation of the number of corresponding fields) is extracted frompicture header information 41 of each packet (step S04).

There are two different picture boundary position extraction methods,and one of these methods is selected depending on the contents of streamdata.

In the first picture boundary position extraction method, an I-pictureposition is detected by detecting the flag of random access indicator503 (FIG. 23( a)) in transport packet header 511 (FIG. 23( b)), a B- orP-picture position is detected by detecting the flag of payload unitstart indicator 501 (FIG. 23( a)).

In the second picture boundary position extraction method, pictureidentification information 52 (FIG. 1 (k)) and PTS information 53 (FIG.1( k)) in picture header information 41 (FIG. 1( j) are extracted.

After the aforementioned processes (steps S01 to S04), the “time relatedinformation generation unit (multiplexed information demultiplexer 425,STB controller 404, data transfer interface 420, and the like in FIG.19)” generates time relationship table 2 (or playback time stamp listPTSL in FIG. 15) as a list which indicates the relationship between thetime stamps (ATS) and PTS values, and records it in work memory 407 inSTB controller 404 (step S05).

Then, packet data (stream data) temporarily saved in memory 426 ofmultiplexed information demultiplexer 425 are transferred to opticaldisc device 415 while maintaining the reception time interval betweenSTB unit 416 and optical disc device 415 (i.e., while maintainingconstant the relationship between a change in count value of STC 440 anda change in count value of STC 424 in FIG. 19) (step S06).

In this way, optical disc device 415 records the stream data temporarilysaved in memory 426 on information storage medium 201 (step S07).

The processes in steps S06 and S07 repeat themselves until stream datatransfer to optical disc device 415 is completed (NO in step S08).

Upon completion of stream data transfer to optical disc device 415 andcompletion of its video recording process (YES in step S08), informationof time relationship table 2 (or playback time stamp list PTSL)temporarily recorded in work memory 407 of STB controller 404 istransferred to optical disc device 415 (step S10).

Information of time relationship table 2 (or playback time stamp listPTSL) is recorded in management information recording area (STREAM.IFO)105 of information storage medium 201 (step S11).

Upon processing step S11, the recording time (SOB_REC_TM in FIG. 7( i))of a stream object as the content of the recorded stream data can berecorded in time zone (TM_ZONE) 6240 (FIG. 7( h)).

Encrypted stream data is often recorded for the purpose of copyrightprotection of the contents provider upon recording stream data. Whenencryption is made in this way, all transport packets are encrypted, anda time stamp transfer process between STB unit 416 and optical discdevice 415 is inhibited. In such case, optical disc device 415 mustindividually append time stamps upon recording (encrypted) stream dataon information storage medium 201.

STB unit 416 in FIG. 19 makes reception time management in units oftransport packets (application packets). In this case, a measure againstreference clock frequency errors (more specifically, synchronization ofreference clocks) between STB unit 416 and optical disc device 415 is animportant subject. Hence, a video recording process of encrypted streamdata will be explained below.

FIG. 25 is a flow chart for explaining the recording sequence ofencrypted stream data according to an embodiment of the presentinvention. This processing sequence can be implemented by a processingprogram stored in program memory 404 a of STB controller 404 shown inFIG. 19.

It is checked if time relationship table 2 (FIG. 20( b)) or playbacktime stamp list PTSL (FIG. 15) is present in work memory 407 of STBcontroller 404 in FIG. 19 (step S50).

If no time relationship table (or PTSL) is present (NO in step S50), thetime relationship table (or PTSL) is generated by the same processes asin steps S04 and S05 in FIG. 24 (step S52).

After the time relationship table (or PTSL) is generated or if the timerelationship table (or PTSL) is already present in work memory 407 ofSTB controller 404 (YES in step S50), (encrypted) stream data istransferred from STB unit 416 to optical disc device 415 and is recordedon information storage medium 201 (step S51).

The process in step S51 continues until recording of the (encrypted)stream data is completed (NO in step S53). This stream data recordingstep S51 has the same processing contents as those in steps S01 to S03and S06 in FIG. 24.

Note that the process in step S52 may be executed parallel to step S51during processing of step S51.

Upon completion of recording of the (encrypted) stream data (YES in stepS53), a reference clock synchronization process is executed between STBunit (or STB device) 416 and optical disc device (or optical disc drive)415 (step S54).

This reference clock synchronization process can be executed, e.g., asfollows.

That is, upon transfer of stream data, every time a specific number oftransport packets (application packets) (e.g., 10,000 or 100,000packets) are sent/received, STB unit 416 and optical disc device 415respectively record the send/reception time in their work memory 407 andtemporary storage 411.

After that, every time STB unit 416 sends a specific number of transportpackets (application packets) to optical disc device 415, it appends asend time list. Optical disc device 415 compares the received list and alist created by itself in advance, thus computing any reference clocksynchronization error therebetween.

After that, STB unit 416 transfers time relationship table 2 (or PTSL)to optical disc device 415 (step S55).

Time relationship table 2 (or PTSL) transferred from STB unit 416 tooptical disc device 415 in this way is corrected on the basis of thereference clock synchronization error computed in the reference clocksynchronization process in step S54 (step S56).

Time relationship table 2 (or PTSL) which has been corrected based onthe reference clock synchronization error is recorded in the managementinformation area (STREAM.IFO 105 in FIG. 3( e); or SFIT in FIG. 15) ofinformation storage medium 201 (step S57).

In this fashion, (encrypted) stream data can be recorded/played back.

In place of the aforementioned method of “correcting the reference clocksynchronization error for encrypted stream data”, another method may beused as follows.

That is, as shown in FIG. 20( b), the number of transport packetstransferred between neighboring I-pictures is recorded in timerelationship table 2. Then, the total number of transport packets (orapplication packets) from the head of a cell is designated in place ofthe time stamp value of a playback start image (as the picturedesignation method).

In this case, the number of transport packets (or the number AP_NS ofapplication packets) included in each stream block is provided asinformation in time map information 252 in place of the data structureshown in FIG. 3( i), as shown in FIG. 11.

When STB unit 416 designates the total number of transport packets (thetotal number of application packets) to access a predetermined image(picture), optical disc device 415 sums up the numbers 633 of transportpackets (application packets) in turn from the first stream block shownin FIG. 11, and accesses a stream block (or SOBU) when the summed-upresult has reached the designated value.

FIG. 26 is a flow chart for explaining the playback sequence of streamdata according to an embodiment of the present invention. Thisprocessing sequence can be implemented by a processing program stored inprogram memory 404 a of STB controller 404 shown in FIG. 19. Theplayback steps of stream data will be explained below using FIG. 26.

The user can designate a desired playback start time and/or playback endtime in the form of a “differential time (xx hours yy minutes zzseconds) with reference to the display start time of the designatedoriginal cell”. STB controller 404 in STB unit 416 receives, e.g., aspecific playback start time and playback end time designated in thisway (step S21).

STB controller 404 converts the time information of the receivedplayback start time and playback end time into clock count values of 27MHz and/or 90 kHz, and computes differential PTS values from the displaystart time of the original cell.

STB controller 404 controls optical disc device 415 to read timerelationship table 2 (or PTSL) recorded in the stream data managementinformation recording area (STREAM.IFO 105), and temporarily records itin work memory 407 (step S22).

Also, STB controller 404 controls optical disc device 415 to read timemap information 252 (or MAPL) recorded in the stream data managementinformation recording area (STREAM.IFO 105), and temporarily records itin work memory 407 (step S23).

Then, STB controller 404 reads the value of PTS offset 9 shown in FIG.3( h) and FIG. 20( a), and checks the difference (PTS No. 5−PTS No. 1 inFIG. 20( a)) between the display start time of the correspondingoriginal cell (corresponding to B-picture f in FIG. 20( a)) and thedisplay time of I-picture a immediately before that picture (step S24).

Furthermore, STB controller 404 reads the value of PTS offset 9 shown inFIG. 3( h) and FIG. 20( a), and computes the PTS values of the playbackstart time and playback end time designated by the user by summing up:

(A) the read value (PTS offset 9),

(B) the PTS value at the I-picture a position immediately before thedisplay start time of the original cell (when display start picture f ofthe original cell is located immediately after I-picture a as in FIG.20( a)), and

(C) the differential PTS value (PTS No. 5−PTS No. 1) checked in step S24(step S25).

STB controller 404 then checks the value of the PTS value of I-picture iimmediately before the playback start position designated by the user,and the value of time stamp #2 using time relationship table 2 (stepS26), and informs optical disc device 415 of them.

The optical disc device checks the value of first time stamp (ATS) #1 ofstream block (SOBU) #A that includes the head position of that I-picturei information (FIG. 21( c)) from data (FIG. 3( i)) of time mapinformation 252 shown in FIG. 3( h), and detects the location (address)of first sector #α to be accessed (step S27).

Based on the detected address, optical disc device 415 plays backinformation from transport packet (AP) #1 in FIG. 21( c) frominformation storage medium 201 (step S28).

STB controller 404 in FIG. 19 then informs decoder unit 402 of the PTSvalue (PTS No. 6 in FIG. 21( a)) indicating the display start time ofinformation which has begun to be played back in step S28 (step S29).

Together with this information, optical disc device 415 transfers theinformation which has begun to be played back in step S28 (step S30).

Subsequently, STB controller 404 reads picture identificationinformation 52 (FIG. 1( k)) from memory 426 in decoder unit 402, anddiscards (or ignores) data before the input I-picture (a portion of theinformation transferred from optical disc device 415) (step S31).

Video decoder 428 in FIG. 19 then starts decoding from the head positionof the I-picture (I-picture i in FIG. 21( a)) input in step S31, andstarts display (video output) from the position of the PTS value (PTSNo. 6 in FIG. 21( a)) designated by the information in step S29 (stepS32).

The same processes as in steps S24 to S28 are repeated, and the addresson the information storage medium 201, which corresponds to the playbackend time is checked to proceed with playback until the end addresscorresponding to the playback end time (step S33).

Upon completion of a series of playback processes, playback end positioninformation 6110 shown in FIG. 7( g) can be recorded as resumeinformation in video manager information (FIG. 7( f)) in the managementinformation recording area (STREAM.IFO 105 shown in FIG. 7( e)).

As the data contents of this playback end position information 6110,corresponding PGC number 6210, cell number 6220 therein, and playbackend position time information 6230 are recorded, as shown in FIG. 7( h).

This time information 6230 is recorded as the time stamp value, but thePTS value (or the total number of fields from the cell playback startposition) can be recorded as time information 6230.

When playback of this playback end position information is restartedfrom the position of (resume) information 6110 based on this playbackend position information, the playback start position can be obtained bythe process shown in FIG. 27 (to be described later).

In standard playback mentioned above with reference to FIG. 26, decodingin decoder unit 402 starts from the time when the count value of STCunit 424 as the reference clock generator in STB unit 416 has matchedthe value of DTS (decode time stamp) information 54 shown in FIG. 1( k).

FIG. 27 is a flow chart for explaining the special playback sequence ofstream data according to an embodiment of the present invention. Thisprocessing sequence can be implemented by a processing program stored inprogram memory 404 a of STB controller 404 shown in FIG. 19.

Upon executing special playback such as fastforward (FF) playback orfast reverse (FR) playback, only I-picture information recorded oninformation storage medium 201 is extracted and played back, and isdecoded and displayed.

In this case, a “special playback mode setup” is made in decoder unit402 to decode in a free mode by canceling synchronization between STCunit 424 (FIG. 19) and DTS information 54 (FIG. 1( k)) (step S41).

In special playback as well, time relationship table 2 and time mapinformation 252 are read from management information recording area(STREAM.IFO) 105 of information storage medium 201, and are recorded inwork memory 407 of STB controller 404 (step S42).

Then, time map information 252 of stream object information (SOBI) 242corresponding to the playback start position of interest is read, and istemporarily stored in work memory 407 in STB controller 404 (step S43).

The time stamp values of the start time/end time at each I-pictureposition (the position of each AU# in the example shown in FIG. 16) arethen extracted from time relationship table 2 (step S44).

A stream block (SOBU) that includes the time stamp value of theI-picture of interest is checked from time map information 252, and theaddress of its first sector is checked (step S45).

Upon special playback, only I-picture information 6010 to 6050 in FIG.28( b) to be described later are decoded and displayed. The positions ofI-picture information 6010 to 6050 can be obtained using the informationof time relationship table 2 and time map information 252.

Optical disc device 415 then plays back information in all stream blocks(SOBUS) that contain I-pictures on information storage medium 201, andtransfers played-back information to memory 426 in multiplexedinformation demultiplexer 425 (step S46).

Decoder 402 in FIG. 19 reads picture identification information 52 (FIG.1( k)) in the data transferred to memory 426 in multiplexed informationdemultiplexer 425, and discards data other than I-pictures on the basisof this information 52 (step S47).

That is, in step S47 only I-picture information is extracted from theplayed back and transferred stream data using picture identificationinformation 52, and video decoder 428 decodes only the extractedI-picture information.

The I-picture data sorted (i.e., not discarded) in memory 426 ofmultiplexed information demultiplexer 425 in decoder unit 402 aretransferred to frame memory 406 (step S48).

The I-picture data transferred to frame memory 406 in this way aresequentially displayed on the display screen of TV (or video monitor)437 (step S49).

FIG. 28 is a view for explaining a time relationship table indicatingthe relationship between the display time and data transfer time inanother embodiment of the present invention.

In the embodiment shown in FIG. 20, absolute value display is made asdisplay time information, as shown in FIG. 20( b). Instead, differentialinformation between neighboring I-pictures (e.g., information indicatingthe number of fields inserted between neighboring I-pictures) may beused.

In FIG. 20( b), “PTS” information is used as the time displayinformation. However, an embodiment of the present invention that allowsvarious modifications is not limited to such specific method. Instead,“the number of differential fields from a specific reference image(picture)”, “date & time information”, or the like can be used. Anexample in this case is time relationship table 6 shown in FIG. 28.

As shown in FIG. 28( b), each group of pictures (GOP) is a picture groupwhich has a given I-picture position as the head position and includespictures from that I-picture to a picture immediately before the nextI-picture. In the data structure of time relationship table 6 shown inFIG. 28( c), the number of display fields in units of GOPs is recordedas display time information.

Also, time relationship table 6 describes the number of stream blocks(SOBUs) occupied in units of GOPs. In this way, a stream block (SOBU)which records the head position of I-picture information can be directlyaccessed from the input display time information without using time mapinformation 252 shown in FIG. 3( h).

At the boundary position between GOP#2 and GOP#3 in the example shown inFIG. 28( b), the switching position of GOPs matches that of streamblocks (SOBUs). When the boundary of neighboring GOPs matches that ofneighboring SOBUs in this manner, a GOP end matching flag in timerelationship table 6 shown in FIG. 28( c) is set at “1”. In this way,identification precision of the stream block position (SOBU position)that includes the I-picture information head position is improved.

Since special playback such as FF, FR, or the like uses the trailing endposition of I-picture information, time relationship table 6 in FIG. 28(c) also has I-picture size information in each GOP.

FIG. 29 is a view for explaining the way packets (AP) in stream data(SOBU) are played back in an embodiment of the present invention.

FIG. 29 exemplifies a case wherein all stream blocks #1, #2, . . . inFIG. 1( c) are made up of SOBU#1, SOBU#2, . . . each having a fixed size(2-ECC block size).

FIG. 29( f) shows the data structure of first sector No. 0 (FIG. 29( e))of SOBU#1, and that of end sector No. 63 (FIG. 29( e)) of SOBU#2 thatneighbors SOBU#1. Although not shown, sectors No. 0 to No. 62 have thesame structure.

As shown in FIG. 29( f), the pack header of a stream pack correspondingto sector No. 0 records system clock reference SCR, and that of a streampack corresponding to sector No. 63 also records system clock referenceSCR.

Assume that a picture to be played back (a picture that the userdesignates using the playback time) is located at the middle of SOBU#2(e.g., the position indicated by AU#1 in FIG. 16). The picture that theuser designates using the playback time corresponds to cell startapplication packet arrival time SC_S_APAT.

In this case, the disc drive (not shown) included in recording/playbackunit 409 in FIG. 19 cannot directly access the middle position ofSOBU#2, and accesses the boundary position between SOBU#1 and SOBU#2.Playback of stream data (STREAM.IFO) 106 in FIG. 29( a) starts from theboundary position between SOBU#1 and SOBU#2.

The interval from the boundary position between SOBU#1 and SOBU#2 to theplayback start position (the position corresponding to SC_S_APAT)corresponds to PTS offset 9 described in FIG. 20( a).

Application packets present between the boundary position between SOBU#1and SOBU#2 and the playback start position (the position correspondingto SC_S_APAT) are decoded but are not played back and output (notdisplayed on the screen). This corresponds to the process in step S31 inFIG. 26.

FIG. 29( g) illustrates that PTS information (PTS value or PTS offset)and application packet AP to be played back are related via timerelationship table 2 in FIG. 20( a).

The relationship between the time relationship table and playback timestamp PTSL shown in FIG. 15 are summarized below.

If ATS represents the time stamp shown in FIG. 1 (g), etc., the PTSvalue included in playback time stamp list PTSL shown in FIG. 15 and ATShave the following relationship:

(1) a stream cell looks up a portion of the recorded bitstream;

(2) AU (normally, I-picture) is a continuous portion of the recordedbitstream (or, AU corresponds to a portion of a cell);

(3) which SOBU includes the AU (I-picture corresponding to a portion ofa cell) is indicated by AUSM (see FIG. 16);

(4) the PTS value is the playback time (display time; or presentationtime PTM) of the corresponding AU (i.e., the PTS value corresponding toAU represents, with respect to playback time, a portion of a cell);

(5) cell start APAT (SC_S_APAT) is the arrival time of applicationpacket AP of the cell of interest (SC_S_APAT corresponds to the PTSvalue with respect to or in association with the playback time);

(6) application packet AP includes time stamp ATS at its head position(see FIG. 29( g),etc.);

(7) the PTS value is included in PTSL (see FIG. 15); and

(8) from the above facts, the PTS value included in PTSL corresponds toATS through the mediation of AUSM, SC_S_APAT, and the like.

Therefore, playback time stamp list PTSL can be regarded as “timerelationship table (FIG. 20( b))” including information (PTS value)indicating the relationship (relationship pertaining to the playbacktime) between the start time (SC_S_APAT) of AU (I-picture) and timestamp ATS of a packet included in the bitstream.

Or, PTSL (time relationship table) can be regarded as informationindicating the correspondence between the PTS value and ATS.

Finally, meanings of some terms used in the description of theembodiments will be summarized below.

-   -   A stream object (SOB) indicates data of the recorded bitstream.        The SR_TRANS.SRO file can record a maximum of 999 SOBs.    -   A stream object unit (SOBU) is a basic unit organized in an SOB.        That is, each SOB is made up of a chain of SOBUs. Especially        after editing, the head SOBU and/or end SOBU of SOB often        contain or contains data which does not belong to an effective        portion of that SOB.

The SOBU is characterized not by the playback time or playback order butby a fixed size (size for 32 sectors or for two ECC blocks).

-   -   An access unit (AU) indicates an arbitrary, single, continuous        portion in the recorded bitstream suitable for individual        playback. This AU normally corresponds to I-picture in the        MPEG-encoded bitstream.    -   An access unit start map (AUSM) indicates an SOBU in the SOB of        interest, which includes the AU.    -   An application packet (AP) is a portion of a bitstream coming        from an application device during recording. Or, the AP is a        portion of a bitstream that goes to an application device during        playback. Such AP is included in a multiplexed transport and has        a fixed size (a maximum of 64,574 bytes) during recording.    -   An application time stamp (ATS) is inserted before each AP, and        consists of 32 bits (4 bytes). The ATS is made up of a basic        field of 90 kHz and an extended field of 27 MHz.    -   A cell (or stream cell SC) is the data structure indicating a        portion of a program. A cell in an original PGC is called an        original cell, and a cell in a user-defined PGC is called a        user-defined cell. Each program in a program set is formed of at        least one original cell. Each portion of a program in each play        list is made up of at least one user-defined cell. In the        streamer, a “cell” indicates a stream cell (SC). Each SC looks        up a portion of the recorded bitstream.    -   The cell number (CN) is a number (1 to 999) assigned to each        cell in a PGC.    -   Stream cell entry point information (SC_EPI) can be used as a        tool for partially skipping recorded contents, and can be        present in an arbitrary stream cell (SC).    -   A start application packet arrival time (SOB_S_APAT) of a stream        object indicates the arrival time of the first AP that belongs        to the SOB of interest. This arrival time is made up of a basic        field of 90 kHz and an extended field of 27 MHz.    -   An end application packet arrival time (SOB_E_APAT) of a stream        object indicates the arrival time of the last AP that belongs to        the SOB of interest.    -   A start application packet arrival time (SC_S_APAT) of a stream        cell indicates the arrival time of the first AP that belongs to        the SC of interest.    -   An end application packet arrival time (SC_E_APAT) of a stream        cell indicates the arrival time of the last AP that belongs to        the SC of interest.    -   Navigation data can be used to control recording, playback,        editing of the bitstream (SOB).    -   A play list (PL) is a list of program portions, the sequence of        which can be arbitrarily defined by the user. PL is described as        a user-defined PGC.    -   A program (PG) is a logical unit of the recorded contents, which        is recognized or defined by the user. A program in a program set        is formed of one or more original cells. A program is defined in        only an original PGC.    -   A program chain (PGC) is a generic unit. In an original PGC, the        PGC indicates a chain of programs corresponding to a program        set. On the other hand, in a user-defined PGC, the PGC        corresponds to a play list and indicates a chain of portions of        programs.    -   Program chain information (PGCI) is the data structure        indicating playback of an overall PGC. The PGCI is used in        either an original PGC or user-defined PGC. The user-defined PGC        is formed of only PGCI, and its cell looks up an SOB in the        original PGC.    -   The program chain number (PGCN) is a serial number (1 to 99)        assigned to each user-defined PGC.    -   The program number (PGN) is a serial number (1 to 99) assigned        to each program in the original PGC.    -   A program set indicates the entire recorded contents of a disc        (recording medium), which consist of all programs. If any        program does not undergo edit that changes the playback order        from original recording, the same playback order as the        recording order of programs is used upon playing back the        program set.    -   “Real-time recording” is a recording performance that can        record, even when a buffer memory size is limited, stream data        on a disc (recording medium) without overflowing the buffer        memory, provided that any stream data encoded at a limited        transfer rate is transferred at the limited transfer rate.

The advantageous effects of the embodiments according to the presentinvention are summarized as follows:

1. By providing information (time relationship table or PTSL) thatindicates the relationship between time stamp data (ATS) recorded instream data and display time information (PTS or field information) to aportion of management information (SFIT), playback/screen display can bestarted with high precision from the display time designated by theuser.

2. The user can designate a partial erase range or re-arrangementdesignation range of the recorded stream data using the display time onthe monitor TV.

As in item “1.” above, the time relationship table (or PTSL) indicatingthe relationship between time stamp data and display time information isprovided as a portion of management information (SFIT). In this manner,the position of edit point (for partial erase range, re-arrangementdesignation range, or the like) can be accurately set using this timerelationship table (or PTSL). As a result, time management for streamdata can be made using time stamp data (ATS), and an accurate editprocess according to a user's request can be guaranteed.

3. As in item “1.” above, since the time relationship table (or PTSL) isincluded in stream data, the playback start position upon restarting thestreamer (resume playback start position) can be accurately set by onlydescribing either time stamp data (ATS) or display time information(PTS) as the playback end position information (resume position).

4. If the playback end position information (resume information) isrecorded using time stamp data (ATS), when a specific position on theinformation storage medium is accessed, the address to be accessed canbe quickly detected using time map information 252.

5. MPEG-compressed data requires playback to start from I-picture. Byrecording information (time relationship table) indicating therelationship between the time stamp data (ATS) and display timeinformation (PTS or field information) at each I-picture start position(or start position of access unit AU), access control to desiredI-picture (desired AU) can be made at high speed using time mapinformation 252.

6. By recording information (time relationship table) indicating therelationship between the time stamp data (ATS) and display timeinformation (PTS or field information) at each I-picture start position(or start position of each AU), the address of the stream block (orSOBU) position including I-picture (AU) can be detected in combinationwith time map information 252. For this reason, a special playbackprocess such as fastforward FF, fast reverse FR, or the like that playsback and displays only I-pictures can be done.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. A bitstream data recording/reproducing apparatus which uses aninformation storage medium having a data area and a management area,said apparatus comprising: a data processing unit configured to providebitstream data based on a first reference clock; a drive unit configuredto record the provided bitstream data in the data area of saidinformation storage medium based on a second reference clock and toreproduce recorded bitstream data from the information storage medium; asynchronizer configured to synchronize the first reference clock withthe second reference clock; a generator configured to generate a timerelation table relating to the first and second reference clocks; and arecorder configured to record the time relation table in the managementarea of said information storage medium.
 2. The apparatus of claim 1,wherein said medium is configured to adopt a data filing scheme having adirectory which includes a data file of bitstream information andanother data file of a real-time video recording object.
 3. A method forrecording bitstream data using an information storage medium having adata area and a management area, said method comprising: providing thebitstream data based on a first reference clock; recording the providedbitstream data in the data area of said information storage medium basedon a second reference clock; synchronizing the first reference clockwith the second reference clock; generating a time relation tablerelating to the first and second reference clocks; and recording thetime relation table in the management area of said information storagemedium.
 4. An information storage medium configured to store thebitstream data and the time relation table in accordance with the methodof claim
 3. 5. The method of claim 3, wherein said medium is configuredto adopt a data filing scheme having a directory which includes a datafile of bitstream information and another data file of a real-time videorecording object.